Maccaferri Channel Design Manual

BANK PROTECTIONREFERENCE MANUAL

Bank Protection

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ACKNOWLEDGEMENT

Maccaferri would like to thank the AIPIN (Associazione Italiana per la Ingegneria Naturalistica - ItalianAssociation of Bio-Engineering) for its help in collecting the necessary literature and data regarding the Bio-Engineering techniques.

Made by E.H.S. S.r.l.P.za di Porta Maggiore, 5 BOLOGNAfor MACCAFERRI

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PART I - REFERENCE MANUAL

INTRODUCTION1. THEORY AND METHODS OF CALCULATION

1.1. General criteria for planning1.2. Methodology of calculation1.3. Hydraulic calculation for open channels1.4. Rating curve

1.4.1. Input data1.4.2. Rating curve calculation

2. BANK LINING CHECK WITH RESPECT TO THE FLOW CHARACTERISTICS2.1. General information2.2. Check in terms of tractive forces2.3. Check in terms of tractive forces for Reno mattress and gabions2.4. Check of deformations for Reno mattress and gabion protections2.5. Check for the water velocity at the upper/lower lining interface2.6. Resistance of sand asphalt mastic grouted Reno mattress and gabion linings2.7. Macmat-R protections2.8. Bank protection using Bio-Engineering techniques2.9. Bank stabilization - Toe protection

3. LINING DESIGN WITH RESPECT TO WAVE MOTION

4. TABLES

5. LEGEND

6. BIBLIOGRAPHY

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INTRODUCTION

The MACRA1/Bank Protection software was developed to provide engineers with a rapid and efficient toolwith which to conduct the stability analysis of watercourse cross-sections with respect to both water flow and wavemotion. This program allows the user to check a large number of hydraulic conditions of watercourse sections linedwith Maccaferri products, such as gabions, Reno mattresses and Macmat-R, as well as with the most widespreadbio-engineering techniques.

The MACRA1/Bank Protection software enables the user to verify, under the hypothesis of uniform flow, ageneric bank protection typology given the allowable tractive force tc and roughness coefficient n, comparing foreach material the maximum shear stress with the allowable tractive force.

The software aims to provide engineers with an open tool where their professional experience and theprogress of the knowledges in the bio-engineering ambit, allow to bring up to date the tc and n values, for whichreference values are given.

In addition, the software facilitates the design of a lining with respect to wave motion (i.e. basins or navigablechannels), providing the Reno mattress thickness needed to guarantee the stability of the bank protection.

To facilitate the use of this software, it was developed using a WindowsTM type structure in order to checksimply and directly the input data and calculation results.

The first part of this manual illustrates the calculation procedures, the hypotheses assumed and their limits ofvariability, the second part illustrates how to use the program, the third part gives a numerical example.

1. THEORY AND METHODS OF CALCULATION

1.1 General criteria for planningIn planning a watercourse, the designer may use three fundamental classes of training and hydraulic protection

structures:- transverse works (weirs, falls, dams) to guarantee the longitudinal stabilization of a watercourse;- groynes, to centralise the direction of the flow which is threatening the stability of the banks;- longitudinal works, defining structures with their length parallel to the river flow. They are used for a variety ofpurposes, such as:

1- flood protection: to guarantee the containment of the flood flow;2- erosion protection of river banks: to avoid situations in which currents erode banks or the toes of banks

rendering both slopes and embankment unstable;3- control of meanders: stabilisation of stream beds to avoid erosion or unacceptable sedimentation;4- delimitation of the normal flow channel: centralization of the low flow channel to guarantee its

navigability or the utilization of the berms.

The Bank Protection software is a tool that allows the user, in the case of longitudinal works, to verify thewatercourse planning with regard to:

- containment of the flood flow: the rating curve computed according to the geometry and the materials whichwill avoid river overflows;

- erosion protection of river banks: the allowable shear stress of the material or technique used in a bankstabilization shall be greater than the maximum active shear stress caused by the water motion.

With such an approach heavy structures, such as gabion walls, reinforced soil structures (e.g. Terramesh), pilewalls etc. will not be taken into account, as they are not really bank protections, but rather retaining structureswhose purpose is to guarantee the overall stability of the embankment, allowing the overhanging bank linings tocarry out their function.

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This is the reason why such structures, whose design reqires calculation methods different from the simplecomparison between active and allowable shear stresses, are not taken into account by the Bank Protectionsoftware; these works are briefly shown in paragraph 2.9 to give general directions for the construction criteria.

Finally it is important to point out that the basic principle of hydraulic planning should be to operate when andhow it is necessary, allowing water to be as free as possible: sometimes, once the designer has evaluated thepotential dangers and risks, the zero option may be taken into account, that is to avoid any work and retain presentconditions.

1.2 Methodology of calculationIn a training and hydraulic protection structure design where Reno mattress, gabions and bio-engineering

techniques are used, the planner shall take into account the vegetation growth over time, (as it modifies theprotection characteristics) and shall refer to two different situations:

The two situations are:

- END OF INSTALLATION:the material or technique used for the structures present the lowest allowable tractiveforce and Manning roughness values. This is the most critical situation to take intoaccount for the bank protection check (see par. 2.2)

- VEGETATION COMPLETELY GROWN: after some years the vegetational growth consolidates the bankprotection which increases its resistance to erosion. Meantime the roughness increase inthe cross-section might cause the failure of the hydraulic check (river overflows)The situation with vegetation completely grown (taking into account a minimum timeequal to 3 years after the end of the installation) becomes the most critical: it is necessaryto check if the cross-section is sufficient to contain the design flow with the new values ofthe roughness n (see par. 1.4)

The Bank Protection software gives the user the roughness and shear resistance values for the situation at theEND OF INSTALLATION: the user shall execute the checks for the situation WITH VEGETATION COMPLETELYGROWN.

1.3 Hydraulic calculation for open channelsThis paragraph contains a summary of the fundamental criteria for the calculations for open channels and some

formulae for the solutions of the most elementary problems in hydraulics. The subject can be studied further byreference to the specialist publications [1, 2, 3, 4]

The types of flow occurring in open channels of fixed cross section (no account is taken of changes of the cross-section caused by erosion or deposition of transported solids, of the influence on the flow by bed load or materialcarried in suspension) can be summarized as follows:

a) VARIED FLOW: when at every point in the mass motion, the velocity, density and pressure characteristicsvary not only from point to point, but also in relation to time.

The behaviour of a water flow can be represented by De Saint Venant equations for the variable motion:

(1)

Qx

At

q+ - = 0

(2)( )

b

tr

Qt

QV

xgA

Zx

BqUw q+ = - - +

0

0

where equation (1) is the law of conservation of mass at constant density, and equation (2) is the law ofconservation of momentum.

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b) STEADY FLOW : when at every point in the mass motion, the velocity, density and pressure characteristics donot vary in relation to time but only from point to point.

By annulling the partial derivatives with respect to time, two new equations which represent the steady flow canbe obtained:

(3)Qx

q- = 0

(4)( )dH

dxBgA

qgA

U Vq= - + -tr

b00

..

Steady flow can be said to occur in the following conditions:- in prismatic channels;- in channels of gradually varying width, depth and bed slope;- in channels in which the width changes suddenly, or the section is restricted abruptly, by rock formations,

bridges, weirs and other structures;- in channels in which the flow varies due to the flow or outflow of water.

For the planning and checking of a steady flow channel you must use the MACRA (Maccaferri River Analysis)software, which allows the designer to take into account the variations of cross-section, roughness and flow typicalof a real watercourse.

c) UNIFORM FLOWIn designing open channels, the flow can be assumed to be uniform, i.e. steady uniform flow in a prismatic

channel having a constant bed slope, and in which the water surface slope is parallel to that of the bed. Hence,uniform flow can be assumed, provided the cross section does not differ greatly from the prismatic form, andprovided there is no backwater effect caused by changes in the cross-section or bed slope upstream or downstream.

Uniform flow is illustrated in fig. I.1; in the case of uniform flow we have ih = iw = if.

Fig I.1 Geometric and hydraulic elements

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By annulling q in (3), (4) and assuming the inclination of the load line equal to the slope of the channel bed,the equation of the uniform motion can be obtained:

(5) Q = constant

(6)dHdx

i f= .

The eq. (6) can be written in the equivalent form (Chezys formula)

(7) Q A Ri f= c

where the roughness coefficient is connected to the Manning coefficient n by means of the relation:

(8) c = -n R1 16/

where

(9) RAB

=

is the hydraulic radius of the cross-section. Writing the equation (7) by means of equations (8) and (9) we finallyobtain the following equation (Manning-Stricklers formula):

(10) Q A B n i f=- -5 3 2 3 1 1 2

.

The symbols used in the above equations and figure correspond to:

A = wetted cross sectional area (m2);B = wetted perimeter (m);b = width of water surface (m);b = momentum coefficient;g = acceleration of gravity (m/s2);H = total hydraulic head (m);if = river bed slope;ih = slope of energy line;iw = slope of water surface;L = length of river segment (m)l = length of horizontal projection of river segment (m);Q = cross-section discharge (m3/s);q = lateral discharge per unit of length (m2/s);r0 = unit weight of water (kg/m

3);t = temporal coordinate (s);t0 = shear stress along the banks (N/m

2);Uq = x component of flow velocity q (m/s);V = mean flow velocity in the cross-section (m/s);x = curvilinear abscissa along the river bed (m);y = maximum depth of water area (m)Zf = level of river bottom in section a-a (m)Zw = level of free water surface (m).

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1.4 Rating curve

The first problem a designer has to solve is to guarantee the containment of the design flow Qp inside the cross-sections where the works have been planned.

The design flow is computed on the basis of hydrological studies or by means of historical measured floodlevels. As a rule the design flow corresponds to a return time equal to 100 years; in the case of rivers which cantolerate floods, one can choose design flows with a smaller return time, thus accepting more frequent inundations.

Beginning from these data, in accordance with the responsible agencies and authorities, one can calculate thewatercourse cross-section or the corresponding water depth, according to cases.

The planner shall guarantee the passage of the design flow through the designed cross-sections; in other words,the following condition must be verified:

(11) Q A B n i f=- -53 2 3 1 12 > Qp

In this check the most critical situation is the one with vegetation completely grown, because this is thecondition with the highest Manning roughness values. The rating curve calculation (and at the same time the bankprotection check) shall be made twice to verify the cross-section in two different conditions:

- end of installation: using the minimum roughness values (tables 1 and 2)- vegetation completely grown: using the roughness values for vegetated banks (tables 3, 4 and 6)

1.4.1. Input data

The user is required to type in the design data, that is the river discharge Qp and the natural bed slope if, or thedesign slope. The user is then required to type in the geometric and hydraulic charateristics of the cross-sectionwhich is generally represented by a double trapezoidal section (Fig.I.2), consisting of 9 segments. fgl and fgrrepresenting the left and right ground level whereas the other seven segments represent the cross-section geometry.For fgl and fgr the user must specify:- the level of the lower edge fi referred to the channel bed (m),- the slope expressed in terms of D Dy x ;for the other segments the user must also specify:- the length li (m).

When required, the i-th segment can be divided into 3 additional sub-segments, i1, i2, i3, (Fig.I.2b), for whichthe user must provide (considering the horizontal segments from the left to the right and the others from the top tobottom):- the length Lij (m),- the type of lining or material.

Depending on the type of lining the program will automatically provide the relevant Mannings roughnesscoefficient nij (s/m

1/3).

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Cross-section i th

- segment

Li1

Li2

Li3

ai1

bi1=ai2

bi2=ai3

bi3

q

qq

qgd

sdss

gsf f

fgl

gsgd

1

23

4

5

6

7

fi

a b

fgr

Fig.I.2. Scheme of the river cross-section

Depending on the type of lining selected the program will also automatically provide (situation at the end ofinstallation), in the case of Maccaferri products (see tables 1 and 5):- the thickness s (m),- the roughness n (s/m1/3),- the average diameter of the filling material dm (m),- the limit (allowable) tractive force tl (kg/m

2).If the user chooses another protection material, the program suggests an indicative value for roughness and

allowable shear stress (see table 2), values which can possibly be modified by the user on the basis of personalexperience.

Table 6 gives the Manning roughness values to be used for natural streams, according to materials constitutingthe bank (or a sub-stretch of the bank), when the material is not included in table 2: in such a case the user cantype in any material for which are known the roughness n and the allowable shear stress tc (see also par. 2.8 and9.5).

The roughness coefficient n can be evaluated, as well as from table 6, using the Meyer-Peter and Mullerformula, valid for gravelly and sandy river beds:

(12) n = 0.0385 d901/6

where d90 is the diameter of a sieve that will permit passage of 90 % of the bed material expressed in meters [5, 6,7].

By using the Manning-Strickler equation, the program automatically calculates the rating curve in uniformflow:

(10) Q A B n i f=- -53 2 3 1 12 .

If the user needs detailed information on the flow velocity, the program will divide the rivers cross-section intoso many parts which will be equal to the number of segments specified by the user, and will calculate theroughness coefficient as the mean roughness with respect to the length of the three sub-segments. The dischargewill be calculated as the sum of the contribution of each single segment (during the calculation, the program willconsider different parallel channels with the same water level and zero shear stress along the banks).

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1.4.2. Rating curve calculationsThis program conducts the rating curve calculation step by step, dividing the total height between river bed and

ground level into 20 equal segments. Therefore starting with a water level equal to fp/20 the program calculatesthe outflow discharge for each segment and the total discharge Qk as the sum of the single contribution of eachsegment. Before proceeding to the next upper water level (by increasing the level by fp/20) the program checks if Qk islower than Qp; if this condition is not satisfied, the program searches, by successive iterations, for the water levelYmax corresponding to Qp . If the design discharge turns out to be equal to a water level higher than the groundlevel, the program will display a message informing the user that the cross-section selected is not able to carry thedesign discharge.

For each segment the program also calculates the mean velocity Vmi :

(13) vQ

Amip

i

=

and the Froude number Fi:

(14) Fv

gAb

imi

i

i

=

with Ai (wetted perimeter) and bi (width of the free water surface) corresponding to Ymax .

2. BANK LINING CHECK WITH RESPECT TO THE FLOW CHARACTERISTICS

2.1. General informations

The calculation (design or verification) of a bank protection can be made using two different methods based on:- velocity- tractive forcesThe second method is more correct from the technical point of view and that is the reason why the Bank

Protection program uses this approach, even if the velocity method is often easier to apply, as it is simpler tomeasure or to calculate an average velocity in a cross-section instead of shear stresses.

In order to evaluate the anti-erosion efficacity of a bank protection, one has to take into account all the hydraulicand geometric parameters: water depth, bank slope, plan configuration, flood duration; this means, in other words,that it is necessary to express the laboratory test results and the consequent design criteria in terms of allowableshear stresses, more significant than water mean velocity from the technical point of view.

It is particularly important also to refer to the flood duration factor as well as the water depth considering anaverage flood duration, and ignoring those of less than a few hours.This factor does not apply to the bankprotections where the shear resistance is due to the material own weight: for rip-rap protection the limit of therevetments stability is when the shear stress is equal to the point at which the stones are about to move (initialmovement stress, which depends only on shape and dimensions of stones). In the case of Reno mattress andgabions, the containment offered by the mesh increases the resistance, allowing a partial stone movement withinthe mattress compartments without risk to the revetment (see par. 2.3).

The data about material (not a stone revetment) resistance as a function of flood duration, are limited to a fewlaboratory-tested materials, i.e. the Macmat-R (see par. 2.7), for which the fig. I.8 shows the permissible shearstresses as a function of the flood duration. In general this kind of detailed information is not available: this is thereason why the shear stress check usually does not take this aspect into account.

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2.2. Check in terms of tractive forces

This method is based on the comparison between the active (depending on the hydraulic and geometriccharacteristics) and the allowable (depending on the material) shear stresses.

ACTIVE STRESSESThe maximum shear stress on the revetment at the bottom is related to the hydraulic radius according to the

formula [1]:

(15) t gb w fRi= . (on the bottom)

For natural watercourses and wide channels the hydraulic radius R is almost equal to the water depth; theprevious formula, valid for a point on the bottom, is therefore (this simplification is in safetys favour):

(16) ( )t gb w i fY z i= -max (on the bottom)

where zi is the elevation of the i-th check point.

If the point is on the banks of a straight line watercourse (in the horizontal plane), the shear stress tm is reducedand is equal to [1]:

(17) ( )t gm w i fY z i= -075. max (on the straight line bank)

Otherwise, in curved canal stretches the shear stress increases along the outer bank by means of the coefficient K,as a function of the ratio of the width of the water surface to the radius of the curvature (see Fig. I.3).

0123456789

10

1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2Ratio of the shear stress on the outer bank to average shear stress

Ratio

o

f the

ra

diu

s o

f the

cu

rvat

ure

to

the

wid

th o

f the

w

ater

su

rfac

e

Fig. I.3 Effect of a curve in the watercourse upon the shear stress acting on the outer bank.

tm is therefore:

(18) ( )t gm w i fK Y z i= -075. max . (on the curved bank)

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RESISTANT STRESSES AND THEIR CHECKRegarding the resistant shear stress, we define maximum (allowable) tractive resistance tc as the critical value

at which the lining material begins to move. In the case of non cohesive soils tc can be obtained using theexpression [9]:

(19) tc = 80 d75

wheretc = maximum (allowable) shear stress (kg/m2)d75 = diameter of a sieve that will permit passage of 75% of the bed material (cm)

The revetment is stable if one can verify, for a point on the bed:

(20) t tb c , (on the river bed)

In the case of non cohesive material laid horizontally, we must take into account the maximum shear stress tsreduction (due to the bank slope) by means of a corrective coefficient; comparing the new ts value with themaximum active stress tm we obtain:

(21) t tm s , (on the sloped bank)

where

(22) t tJjs c

sinsin

= -12

2

and where:j = angle of internal friction of the non cohesive material forming the bankq = bank side slope.

Since the value under the square root tends to 0 and becomes negative for values of J > j, the program allowsus to calculate ts assuming that for bank slopes q > (j - 2) the value of the square root remains constant and equalto

(22) t tJ

js csin

sin= -

-1

222

( )

providing a residual resistance to the material.To determine the friction angle in non cohesive materials, when no laboratory test is available, the abacus

shown in fig. I.4 can be used

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Fig. I.4 Abacus to establish the friction angle for non cohesive materials

2.3. Check in terms of tractive forces for Reno mattress and gabions

Gabion and Reno mattress structures present a spontaneous vegetation growth helping the natural recovery ofdestroyed or damaged biocenosis. Vegetation and gabions/Reno mattress have shown their ability to co-exist andprovide to one another favourable conditions to development: this statement can be considered as a milestone ofbio-engineering which is aimed at combining living and artificial materials for the protection works intended tocounteract erosion [10].

On the basis of this evidence one can assume that the resistent shear stress values for vegetated Reno mattressand gabions (table 3) are independent from the revetment thickness, as the interlacing between stones, wire mesh,soil fill, roots and natural soil forms a single structure whose resistance is due to the mobilization of its differentcomponents.

In general, a stone revetment is considered to be stable when there is no movement of the individual stones. Thisholds true for Reno mattress and gabion revetments in which the stone is encased in steel wire mesh, and also forthose of loose stone rip-rap. For these structures the limit of the revetments stability is when the shear stress isequal to the point at which the stones are about to move (initial movement stress). The active shear stress on therevetment is given by eq. (16)

Given a stone having an equivalent diameter equal to the mean diameter dm of the fill (that is the seive sizethrough which 50% of the stone in the revetment will pass) the dimension given by the following expression isdefined as Shields parameter.

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(23) ( )

Cd

c

s w m

* =-t

g g

The denominator is proportional to the normal stress on the invert due to the submerged weight of the stone; theShields parameter is therefore analogous to a friction coefficient. The shear stress on the invert that can bereached without stone movement (critical shear stress) is therefore:

(24) tc = C* (gs - gw) dm

The revetment is stable if one can verify the inequality found by comparing equation (16) with equation (24):

(20) tb < tc

With limited deformation, to take into account the stabilizing effect due to the wire mesh, one can admit forgabions and Reno mattress an increase of resistance equal to 20 %, as with this value we have limited deformationdue to the stone movement. With tl defined as limit shear stress one has to compare

(25) tb < tl

where tl = 1.2 tc

The Shields parameter for loose stone rip-rap is about 0.047; for stone contained in steel wire mesh (Renomattress and gabions) it is [5]:

(26) C* @ 0.10

Given the same size stones, the filling in Reno mattress and gabions can withstand more than double the shearstress that rip-rap can, because of the containment by the steel wire mesh.

The roughness and resistent shear stress obtained from laboratory tests [5] are shown in table 1 (situationwithout vegetation growth); the values for the situation with vegetation completely grown are shown in table 3.

The preceeding expressions refer to the lining of the channel invert; for the banks the shear stress can beexpressed:

(22) t tJjs c

sinsin

= -12

2

where j is the angle of internal friction of the stone fill; it can be assumed for Reno mattress that j = 41 [5].Since the value under the square root tends to 0 and becomes negative for values of q 41 , the program

assumes that for q 39 the value of the square root remains constant whereas for q = 39 this value remainsequal to the assumed value.

In curved canal stretches the shear stress increases along the outer bank will increase according to par. 2.2

2.4 Check of deformations for Reno mattress and gabion protections

These calculations are not made by the program.When the shear stress reaches the critical value of the condition of initial movement, part of the stone fill

moves downstream inside each compartment of the Reno mattress (fig. I.5).

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Fig. I.5 General pattern of stone movement within the mattress compartment

If the shear stress further increases, one of two things may happen: either the revetment will lose effectiveness (ifthe base soil under the Reno mattress becomes exposed) or a new equilibrium will be reached in which the strengthof the steel wire mesh allows it to fulfill its containment function.The degree of protection offered by the Reno mattress to the underlying base soil remains unchanged even after

this deformation (providing the base materials are not exposed) since the velocity of the water under the Renomattress does not change significantly.To evaluate the degree of deformation a parameter Dz/dm is used, where Dz is the height difference between the

highest and lowest rock surface within a mattress compartment. It can be defined as effective Shields parameter:

(27)( )

( )C

dm s

s w m

*'=-

-t t

g g

The relationship of Dz/dm and C* is expressed by the curve in fig. I.6.

00.20.40.60.8

11.21.41.61.8

0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.1 0.11 0.12Effective Shields parameter C'*

Defo

rmat

ion pa

ram

eter

Dz

/dm

Fig. I.6 Relationship between the deformation factor and the effective Shields parameter

The reduction in the filling rock thickness in the upstream portion of the Reno mattress compartment is Dz/2;therefore to insure that the underlying soil does not remain unprotected and exposed directly to the current, it isessential that:

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(28) ( )Dz d s dm m -2 1 .

where s is the mattress thickness.The same procedure for evaluating the acceptability of deformations is followed also for the Reno mattress on

the banks. From laboratory tests [5] it can be seen that beyond certain values of C* the factor Dz/dm does notincrease; for this reason Reno mattress of a thickness 1.8-2.0 times the size of the stable stone can withstandmuch more adverse conditions than those of the initial design without losing effectiveness. tb can be allowed toexceed tc but not by more than 20%; it is still necessary, however to control the deformations for a given designflow.

2.5 Check for the water velocity at the upper/lower lining interface

In both Reno mattress and gabion linings and rip-rap, the thickness of the lining and the size of the stones mustresist the movement caused by the current and prevent erosion of the face material.

The velocity vb of the water at the interface with the stone layer and the base soil must therefore be slow enoughnot to move the particles that form the soil.

Since the velocity of the water under the revetment depends mainly on the slope of the channel and on the sizeof the voids between the stones, (that is, on the size of the stones themselves), assuming that the predominantdirection of flow is parallel to the surface of the Reno mattress, the velocity will remain practically constant in theface of varying hydraulic conditions and thicknesses of the Reno mattress. The velocity under the Reno mattresslaid on the river bottom, at the interface with the base soil or with the filter, can be determined from the Manningformula.

(29) vn

dib

f

mf=

12

2 3

,

where nf is the roughness coefficient of the bottom equal to:

nf = 0.02 if there is a geotextile filter or no filter under the Reno mattress;nf = 0.025 if there is a gravel filter.

Velocity vb must be compared to velocity ve allowable at the interface with the base material.The ve for cohesive soil can be obtained from fig. 1.7.

Fig. I.7Maximum permissible velocities for cohesive soils

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For cohesionless soil the expression is:

(30) v de = 161. ,

where ve is expressed in m/s and d (m) is the soil particle size to be retained.

Where geotextile filters are used, the velocity of the flow passing through the geotextile is reduced. At theinterface with the soil it is 1/2-1/4 of the value of vb obtained from (29), depending on the type of geotextile. Theprogram takes into account a medium geotextile and assumes that vb under the geotextile is equal to 1/3 the valuegiven by (29).

If using a geotextile filter under the mattress, the water velocity at the filter/soil interface is more than thepermissible velocity, it will be necessary to employ a gravel filter (this check is not made by the program). Such afilter should have a thickness between 0.15 and 0.20 m and at least greater than:

(31) Sdf

vv

v e

b

= -

12

,

where f is the Darcy-Weisbach coefficient (it may be assumed as f=0.05) and dv is the equivalent voids diameter(m). This latter may be assumed to equal 1/5 of the gravel filters average particle size:

(32) dd

v

filter

= 505

( )

.

The grading of the filter is determined by the following equations [11]:

(33)dd

filter

soil50

50

40( )

( ) ,

(34) 5 401515

dd

filter

soil

( )

( ) ,

(35)dd

filter

soil15

85

5( )

( ) .

2.6. Resistance of sand asphalt mastic grouted Reno mattress and gabion linings

Grouting with sand asphalt mastic, whether for consolidation only or for the complete filling of the voids, givesthe lining monolithicity and also a greater total weight; therefore the resistance to flow is improved. In particular,the mastic keeps the rocks from moving inside the mattress and so the condition of initial movement cannot beused to define stability.

The mode and cause of deformation is completely different to that of ungrouted Reno mattresses and gabions;therefore grouted linings can be used for much more severe conditions.

Mastic grouted Reno mattress and gabions are used, besides cases of high resistance structures such as slopedweirs, where impermeability and a smooth surface to reduce the roughness factor are required.

In Table 1, the values of the allowable shear stresses of grouted mattress (thickness 0.23-0.25 cm) are shown [5].

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2.7. Macmat-R protections

In the case of bank protections made with Macmat-R, the allowable shear stresses of the material have beenevaluated by means of experimental studies carried out in the USA [12] and in Europe [13]: the test results areshown in fig. I.8, where the Macmat-R allowable tangential shear stress is shown as a function of the floodduration time.

The curve was obtained using a factor of safety of 3, in accordance with normal practice in this particular fieldof engineering, in terms of the figures obtained for a saturated soil protected only by a three-dimensional geogrid,without a cover of vegetation, as this may be considered the worst case.

02.5

5

7.5

1012.5

15

17.5

20

0 5 10 15 20 25 30 35 40 45 50Flood duration (hrs)

Allo

wa

ble

s

hea

r s

tre

ss

(K

g/m

2)

Fig. I.8 Macmat-R allowable shear stress as a function of flood duration

The values shown in fig. I.8 are valid at the bottom of straight lines: in the case of a bank sloping at q to thehorizontal, it is possible to calculate the critical shear value on the slope. If the slope is on the outside bank of abend in the river the active shear stress may be obtained by including the K coefficient (see par. 2.2).

2.8. Bank protection using Bio-Engineering techniques

Bank protection works aim to stabilize the bank areas and carry out their protective function at the transitionpoint between water and soil, protecting the banks from stream actions and the transport of solids.

From the various bio-engineering techniques available to a designer, the Bank Protection software suggests themain ones, providing the corresponding roughness and resistant shear stress values obtained from the technicalliterature.

The values shown in table 2 [1, 14] have to be seen as temporary and shall be modified on the basis of thelaboratory and on-site test results, but they allow the user to have a reference range from which to select the correctdesigns.

For this kind of technique the resistant shear stresses have been obtained from experimental observations duringflood events and shall be taken into consideration as the values measured up to now without rupture of therevetmnent.

The software provides, besides some natural river materials (sand, gravel, cobbles) the following main bio-engineering techniques:

1) Grass mats2) Cutting-Shrubs3) Brush mattress with willow4) Riparian wattle fences5) Willow protection6) Vegetated rock wall

For each of them, the typical sketch is shown in fig. I.9.

Bank Protection

19

Fig. I.9: Main Bio-Engineering techniques

The software enables the user to verify a generic bank protection typology: the user shall type in the techniquename, the allowable tractive force tc and roughness coefficient n (see Reference manual)

Bank Protection

20

2.9 Bank stabilization - Toe protection

When, besides the simple bank protection, it is necessary to guarantee the retaining/reinforcement of the bank tobe protected, the designer will have to take into account other structures, such as gravity structures, reinforced soilstructures and toe protection works where the foundation dimensioning must be particularly accurate to avoidfailures caused by erosion at the toe of a bank.

The design of such structures shall be done according to geotechnical principles to guarantee the overallstructure-soil stability; for each of them the typical sketch is shown in fig. I.10:

- Gabion wall: design is made by means of the GAWAC software- Green Terramesh: design is made by means of the MACSTARS software- Terramesh System: design is made by means of the MACSTARS software- Pile wall: for design criteria see [15, 16]- Fascine along the toe of embankment: for design criteria see [15, 16]

Fig. I.10 Typical sketches of some bank stabilization and toe protection structures.

Bank Protection

21

3. LINING DESIGN WITH RESPECT TO WAVE MOTION

The banks of large canals, irrigation basins and large lakes are subject to wave action generated by wind in thesame way as the seashore; also navigation canal banks are subjected to wave action caused by vessels, whichinduces waves of a height which depends on the velocity and dimensions of the vessel and the cross section of thecanal. The principal parameters in designing revetments for this purpose are the wave height and the bank slope.

The equations utilized by the program to check the linings ability to resist wave motion (Reno mattresses andgabions) refer to some field trials conducted by Brown and Pilarczyk [17]. These equations are used to find thelinings minimum thickness tm :

(37)( )

tH

n mms=

-21 D cota,

valid for cota 3, that is:

(38)( ) ( )

tH

n mm

s=-41 13D cota

,

valid for cota 3. Hs is the design wave height, a is the linings inclination angle, n is the material porosity and

Dm the unit weight of the submerged material (D m s ww

=-g g

g).

In most cases, ( )1 1- @n mD , and (37) and (38) yield:

(39) tH

ms=

2cota

for cota 3,

(40)( )

tH

ms=

413

cota

for cota 3.

WARNINGThese equations are valid both for wind-induced waves lower than 1 m, and infrequent waves 1.5 m high (due to

boats passing through). In the case of higher waves the soil under the lining and the filling material must beproperly compacted.

4. TABLES

The following tables give the fundamental parameters (tc tl n) taken into account in the bank protectioncalculation, where:

ttc critical shear stress: value of the maximum shear resistance for the material (or technique) laid horizontally.ttl limit shear stress: (only for gabions and Reno mattress) value of the maximum shear resistance for the materiallaid horizontally, causing acceptable deformations due to the stones movement. This is the value used by thesoftware to check Reno mattress and gabion protections (situation at the end of the installation).

Bank Protection

22

SITUATION AT THE END OF INSTALLATION

MACCAFERRI PRODUCTS END OF INSTALLATIONRoughness n

(s/m1/3)Allowable tractive force ttl

(N/m2)Gabions 50 cm 0.0301 342

Reno Mattress 15-17 cm 0.0277 204Reno Mattress 23-25 cm 0.0277 234

Reno Mattress 30 cm 0.0277 270Mastic grouted R.M.23-25 cm 0.0158 324

Macmat-R 0.0303 35-160 (a)(a) = function of the flood duration (see fig. 1.8)Tab.1: Allowable tractive force and roughness values for Maccaferri products at the end of installation [5, 11]

B.E. TECHNIQUES END OF INSTALLATIONRoughness n

(s/m1/3)Allowable tractive force ttc

(N/m2)Fine sand (< 0.2 mm) 0.02 2

Gravel (< 2 cm) 0.02 15Sand and gravel 0.03 30

Cobbles and shingles 0.035 50Grass mats 0.04 10

Cutting - Shrubs 0.10 10 Brush mattress with willow 0.10 50

Riparian wattle fences 0.10 10 Willow protection 0.10 20

Vegetated rock wall 0.04-0.07 (b) (c)(b): The coefficient shall be computed on the basis of the real typology of the work, taking into account shape anddimensions of the stones using equation (12).(c): The actual resistant shear stress depends on the stone dimensions and may be computed using the equation(24)Tab.2: Reference values of the allowable tractive force and roughness for some natural materials and for somebio-engineering techniques at the end of installation [1, 14].

SITUATION WITH VEGETATION COMPLETELY GROWN

MACCAFERRI PRODUCTS VEGETATION COMPLETELY GROWNRoughness n (s/m1/3) Allowable shear stress ttc

(N/m2)Gabions 50 cm 0.07-0.4 (d) 400

Reno Mattress 15-17 cm 0.07-0.4 (d) 400Reno Mattress 23-25 cm 0.07-0.4 (d) 400

Reno Mattress 30 cm 0.07-0.4 (d) 400Mastic grouted R.M.23-25 cm 0.07-0.4 (d) 400

Macmat-R 0.07-0.4 (d) 300(d) = depends on the vegetation growth (see table 4)Tab.3: Allowable tractive force and roughness values for Maccaferri products with vegetation completely grown

Bank Protection

23

B.E. TECHNIQUES VEGETATION COMPLETELY GROWNRoughness n (s/m1/3) Allowable shear stress ttc (Kg/m2)

Fine sand (< 0.2 mm) 0.02 (d) > 0.2 (d)Gravel (< 2 cm) 0.02 (d) > 1.5 (d)Sand and gravel 0.03 (d) > 3 (d)

Cobbles and shingles 0.035 (d) > 5 (d)Grass mats 0.05 (d) 3

Cutting - Shrubs 0.07-0.4 (d) 6 Brush mat. with willow 0.07-0.4 (d) 30 Riparian wattle fences 0.07-0.4 (d) 5

Willow protection 0.07-0.4 (d) 10 Vegetated rock wall 0.07-0.4 (d) 35 (e)

(d): depends on the vegetation growth (see table 4)(e): The actual resistant shear stress depends on the stone dimensions and may be computed using the equation(24)Tab.4: Reference values of the allowable tractive force and roughness for some natural materials and for somebio-engineering techniques with vegetation completely grown [1, 14].

MAIN CHARACTERISTICS OF MACCAFERRI PRODUCTS

MACCAFERRI PRODUCTS Thicknesss (m)

Average diameterd50 (m)

Gabions 50 cm 0.5 0.19Reno Mattress 15-17 cm 0.15-0.17 0.11Reno Mattress 23-25 cm 0.23-0.25 0.12

Reno Mattress 30 cm 0.3 0.125Mastic grouted R.M.23-25 cm 0.23-0.25 0.12

Tab. 5: Thickness and average diameter of the filling stones for Reno mattress and gabion protections.

Bank Protection

24

MINOR STREAMS (top width at flood stage < 30m) Minimumn

Normaln

Maximumn

Streams on plain1. Clean, straight, full stage, no rifts or deep pools 0.025 0.030 0.0332. Same as above, but more stones and weeds 0.030 0.035 0.0403. Clean, winding, some pools and shoals 0.033 0.040 0.0454. Same as above, but some weeds and stones 0.035 0.045 0.0505. Same as above, lower stages, more ineffective slopes and sections 0.040 0.048 0.0556. Same as 4, but more stones 0.045 0.050 0.0607. Sluggish reaches, weedy, deep pools 0.050 0.070 0.0808. Very weedy reaches, deep pools, or floodways with heavy stand of timber andunderbrush

0.075 0.100 0.150

Mountain streams, no vegetation in channel, banks usually steep, trees andbrush along banks submerged at high stages9. Bottom: gravels, cobbles, and few boulders 0.030 0.040 0.05010. Bottom: cobbles with large boulders 0.040 0.050 0.070

FLOOD PLAINS

Pasture, no brush11. Short grass 0.025 0.030 0.03512. High grass 0.030 0.035 0.050

Cultivated areas13. No crop 0.020 0.030 0.04014. Mature row crops 0.025 0.035 0.04515. Mature field crops 0.030 0.040 0.050

Brush16. Scattered brush, heavy weeds 0.035 0.050 0.07017. Light brush and trees, in winter 0.035 0.050 0.06018. Light brush and trees, in summer 0.040 0.060 0.08019. Medium to dense brush, in winter 0.045 0.070 0.11020. Medium to dense brush, in summer 0.070 0.100 0.160

Trees21. Dense willows, summer, straight 0.110 0.150 0.20022. Cleared land with tree stumps, no sprouts 0.030 0.040 0.05023. Same as above, but with heavy growth of sprouts 0.050 0.060 0.08024. Heavy stand of timber, a few down trees, little undergrowth, flood stage belowbranches

0.080 0.100 0.120

25. Same as above, but with flood stage reaching branches 0.100 0.120 0.160

MAJOR STREAMS (top width at flood stage >30 m)

The n value is less than that for minor streams of similar description, becausebanks offer less effective resistance.

26. Regular section with no boulders or brush 0.025 ...... 0.06027. Irregular and rough section 0.035 ...... 0.100Tab. 6: Values of the roughness coefficient n in natural streams [1]

Bank Protection

25

5. LEGEND - (Measurement Units expressed with the Technical System)

Input data for the rating curve calculation:Qp = design flow (m

3/s);if = slope of invert (%);Li = length of the i-th segment (m);fi = elevation of the lower edge of the i-th segment (m)

1

fg = ground level (m)1;

qi = slope of the i-th segment (deg);ni = Manning roughness coefficient of the i-th segment (s/m

1/3);

Values calculated during the first step (rating curve):Ymax = water level corresponding to the design flow (m)

1;vmi = mean flow velocity along the i-th segment relevant to the design flood (m/s);Fi = Froude number relevant to the i-th segment and to the design flood (adim).

Input data to run the lining stability check against flow velocity:t = flood duration (hrs.), (this parameter is required only in the case of a Macmat-R lining);tc = allowable shear stress along the horizontal segments (kg/m2);s = lining thickness (m);j = internal friction angle of the material forming the bank (deg); default value = 30, for gabions

and Reno mattress the value is 41;gw = water unit weight (kg/m3); default value = 1000 kg/m3;ve = admissible maximum flow velocity under the lining (m/s);dm = mean diameter of the filling material (m);nf = channel bed roughness coefficient, default value = 0.020 valid whether or not a geotextile filter has been

considered under the lining. Conversely the default value is equal to 0.025 if a gravel filter has beenconsidered;

K = coefficient of increment of the shear stress on the outer bank along a bend (adim);

Results of the lining check against flow velocity:tb = maximum active shear stress along the horizontal segments (kg/m2);tm = maximum active shear stress along the banks (kg/m2);ts = allowable shear stress on the banks (kg/m2);vb = flow velocity under the lining (m/s) calculated using Mannings equation;

Input data to design the lining against wave motion:Hs = design wave height (m);a = slope of the revetted area (rad);

Calculated values:tm = minimum lining thickness (m).

1 All elevation are referred to the river bed.

Bank Protection

26

6. BIBLIOGRAPHY

[1] V. T. CHOW, Open channel hydraulics, Mc Graw - Hill Book Co., New York, Toronto, London, 1959.

[2] U. PUPPINI, Idraulica, Ed. Zanichelli, Bologna, 1947.

[3] G. SUPINO, Idraulica generale, Ed. Patron, Bologna, 1965

[4] B. PRZEDWOJSKI, R. BLAZEJEWSKI, K. W. PILARCZYK, River training techniques, Balkema,Rotterdam, Brookfield, 1995

[5] D.B. SIMONS, Y. H. CHEN, L. J. SWENSON, Hydraulic test to develop design criteria for the use ofReno mattresses, Fort Collins, Colorado, 1983.

[6] D.B. SIMONS, LI & ASSOCIATES, Consideration of risk in hydraulic design of bank protection usingReno mattresses and rip-rap, Fort Collins, Colorado, 1983.

[7] D.B. SIMONS, R. H. LI, W. S. LIANG, Design guidelines & criteria. Channels & hydraulic structureson sandy soils, Fort Collins, Colorado, 1981.

[8] B. LACHAT Guide de protection des berges de cours deau en techniques vegetales, Ministere delEnvironnement - Diren Rhone Alpes, 1994.

[9] A. LENCASTRE, Manuel dhydraulique generale, Ed. Eyrolles, Paris, 1979.

[10] V.N. MARTINO E ALTRI, Ricerca sulle implicazioni ambientali di opere in gabbioni e materassi Renoin ambito fluviale, Compositori, Bologna, 1995.

[11] U. S. DEPARTMENT OF THE ARMY CORPS OF ENGINEERS, Wire mesh gabions (slope andchannel protection), CW-02541, 1980.

[12] L. HOFFMAN & R. ADAMSKY, Nylon erosion control mat - Presented at session 136 of the 61stAnnual Meeting of the Transportation Research Board, Washington D.C., 1982.

[13] CIRIA, Designed of reinforced green waterways, Report 116, 1987.

[14] W. BEGEMANN & H. M. SCHIECHTL, Ingenieurbiologie - Handbuch zum naturnahen Wasser undErdbau, Bauverlag, Wiesbaden und Berlin, 1986.

[15] MINISTERO DELLAMBIENTE, Opere di ingegneria naturalistica sulle sponde - Tecniche costruttiveed esempi nel Cantone di Berna (Svizzera), Roma, 1993.

[16] REGIONI EMILIA-ROMAGNA E VENETO, Manuale tecnico di ingegneria naturalistica, Bologna,1993.

[17] PIANC, Guidelines for the design and construction of flexible revetments incorporating geotextiles forinland waterways, Supplemento al bollettino n57, Brussels, 1987.

MACRA 1 Manual / Bank Protection

1

PART II - USERS MANUAL

INTRODUCTION

The MACRA1/Bank Protection software was developed to operate in a Windows environment: it was thereforeprovided with several simple options. It is fairly simple to use even if the user is not familiar with a PC.

Chapter 7 illustrates the program installation procedures and its supporting files. Chapter 8 briefly reviews the main basic concepts to allow the amateur user to operate the program. Chapter 9 illustrates how to run the program and its possible options.

7. SOFTWARE INSTALLATIONThe Bank Protection software is supplied in a floppy disk 3 format. To install it, the user must insert the floppydisk in drive A: and proceed as follows:

If you are in Windows:1) You must quit all active Windows applications including the clock, the antivirus etc.;2) Select the Install option from the File menu;3) Type a:setup.exe and press Enter.

If you are in DOS:

4) you must enter Windows;5) then proceed from point 1).

At this point you must follow the instructions provided by the installation program. In particular, the programwill show you the name of the directory (c:\Macra) where the Bank Protection software will be installed.

If the instructions are properly followed, the MACRA software window with the icon to activate the program(MACRA 1) will be displayed on the screen.

WARNING!!During the Bank Protection software installation two different message boxes could appear:- the first one asks the user to close some active Visual Basic applications: in such case, click the OK button;

- the second one:

warns that the file COMMDLG.DLL is already in use: in this case you have to click the Ignore button;

BUT BE CAREFUL!! The program runs properly if Windows considers the dot (.) as a decimal separator and thecomma (,) as a separator of the thousands. If Windows has a different current layout, you must modify it byentering the option International on the control panel (for additional detail refer to the Program Managerinstruction guide).

By hitting twice on the channel icon you can run the program and go to the following chapter for detailedinformation on the MACRA1/Bank Protection software capabilities and instructions on how to use it.


2

8. BASIC INSTRUCTIONS ON HOW TO USE WINDOWS APPLICATIONSWindows has been developed to provide the user with a direct interface. The pointing device, the pull down

menu, the graphic buttons and many other functions make it very simple to move within a Windows program.The Bank Protection software has been provided with most Windows options to prevent the user from panicking

while he uses an application that he is not familiar with.The help function (always available), the error messages (as specific as possible), the possibility to move from

one step to another without an imperative hierarchical order and many other functions allow the use of thissoftware in a flexible efficient way.

In order to make the user acquainted and comfortable with some Windows applications, some simpleinformation on the main elements of this environment are provided below.

Fig.II.1 shows the menu bar of the Bank Protection software which is very similar to the menu bar of anyWindows application.

Fig.II.1

By selecting one of the menus available, a series of options will be displayed (see Fig.II.2: in this case the filemenu has been selected):

Fig.II.2

The File menu consists of a series of I/O (Input /Output) options.Each option has a different function: for example Open ... and Save as... end with 3 dots, which means that the

user must provide additional data (i.e. the name of the file the user needs to open or create)The option New Cross-section, instead, appears with a grey background rather than black, which means that the

user cannot select the type of cross-section until the rivers general parameters have been provided.


3

Fig.II.3

Fig.II.3 shows a window with graphic elements, input fields and an OK button to confirm your choice, whichcan be used only to type in the river general parameters.

As you will notice, one of the flow input fields in Fig. II.3 has a different color since that field has beenactivated and the relative value can be typed in.

To move from field to field you can:1) move your pointing device to the field you wish to activate and press the left button once;2) move from field to field using the TAB key (to move from the upper to the lower field) or ALT+TAB (to move

from the bottom to the top field);3) move your pointing device to the section of the drawing which represents the desired field and press the left

button of your mouse (i.e. by moving your pointing device onto the segment line representing the channel bedand, clicking once, you will activate field i).

The user must remember that he/she is allowed to modify or type in only one value at a time. In order to changethe input data of one field the user must first activate the desired field and this will automatically disable the fieldpreviously activated. The program automatically checks the numerical value you type in. If this value is not correct(from an hydraulic point of view), you will not be able to move to another field until you delete or modify the inputvalue.

Once you have typed in all required input data you must press the OK button to confirm. The program will warnyou if you accidentally click the OK button when you are still typing in the input data.

Some windows may be provided with graphic buttons rather than dialogue buttons.


4

Fig.II.4

Fig. II.4 shows a window with action buttons performing specific functions: for example if you pick, with yourpointing device, the open faucet button the program automatically conducts the hydraulic calculations.

The above basic instructions will enable you to run and use the Bank Protection software. If you need additionalinformation on Windows you may resort to the Windows help guide by pressing F1 from the Program Manager.


5

9. HOW TO USE THE BANK PROTECTION SOFTWARE

Once you have entered the MACRA1/Bank Protection software, the Maccaferri logo will be displayed. By pressingonce the left botton of your mouse you will enter the software operative section.

9.1. General information

The MACRA1/Bank Protection software operates in a Windows environment: therefore you can enter otherWindows applications without quitting the program (this operation is referred to as multitasking) as follows:1) by pressing CTRL+ESC simultaneously: this key combination allows you to display all active applications and

by selecting the option Move to.... to enter one of them;2) by using the key combination ALT+TAB you can enter directly into another application;3) by clicking on the quit button located on the menu bar (located on the upper left side of the screen) and then

select the option Move to.....

9.2. Menu bar

Once you have entered the Bank Protection software operative section, the menu bar with several options will bedisplayed on the screens upper edge (Fig.II.1 - the user may move this anywhere on the screen). The followingparagraphs will illustrate how to use the menu bar.

9.2.1. File Menu

The File menu (Fig.II.5) is used to manage the input and output data.

Fig.II.5

By selecting the option New alveous the user can type in the input data of a new river (slope and discharge flow)thus deleting all data previously provided and nulling the calculations already conducted. Therefore when you typein new data save them before starting a new design.

The option New Cross-section allows you to select a new river cross-section maintaining the input data previouslyprovided. Even in this case if the user has not saved the cross section previously selected it will be replaced withthe new one.

By selecting the option Open File... the window shown in Fig. II.6 will be displayed:


6

Fig.II.6

The program will display on the left side of the window all files of the directory selected. Once a file has beenselected the user can enter it by clicking the OK button or pressing enter. The program will load the file selectedsubstituting the current data.

N.B. This option must be carefully used: in fact when the user has typed in new data and then opens an existingfile, the program will automatically open the modify file window (Fig. II.14).

The option Save File is used to save the data file previously opened. This operation is allowed only if the user isoperating with an existing file: the name of the file is always displayed on the screens upper edge. In the case of*.* (which means that the new input data has not yet been saved with a name) the program will display an errormessage.

The option Save File as... is used to save both an existing or a new file. This option operates similarly to the optionOpen File ... but in addition the user must indicate the file name and its extension which must always be *.DTC.

The option Print Report allows the user to print the printpreview of the cross section analyzed and a numericalreport showing both the input and output data.

The option Save report as... allows you to save the project input and output data. You are also required to provideboth the file name and extension *.RSC. Save report and Save File as ... are very similar options except for thefile extension.

If you select an existing file you must add the last results obtained or delete them by rewriting a new document orchanging the file name.N.B.: This type of file cannot be read by the Bank protection software through the option Open File.... To read orprint it you can resort to any editor (i.e. the MS-DOS editor or a video writing program such as Word forWindows,...).

The option Create .DXF file... saves the drawing of the section examined on a *.DXF file with a name providedby the user. The drawing will have the abscissae and the ordinates of the main points of the cross-section: the pointof origin of the reference system is located on the drawings leftmost lower edge where the first and the secondnumber represent respectively the abscissa and the ordinate.

The option Exit ends the program.


7

9.2.2. Options Menu

The Options Menu (Fig.II.7) allows you to select the language, the unit of measure and the screen backgroundcolor: your choice will be maintained until you end your working session.

Fig.II.7

The option Language allows you to choose the language you feel most comfortable with. The options available are:Italian, English, French and Spanish. You can select any language any time: the program will instantly translatethe legend and convert both input and output data.

The option Unit of Measure is used to choose the desired unit of measure: International, Technical or AmericanSystem. You can modify your choice any time. Users must be aware that by saving a file, the program willmaintain the unit of measure used but not the language. For example if you have previously saved a file using theItalian language and the technical system, if you enter this file and change the language and the systemrespectively into English and American, when you save this file again, the program will keep the English languagebut will change the American into the Technical system.

By selecting the option Screen color... you can personalize the screen background color. You can select one ofWindows standard colors or create your own.

9.2.3. Calculate Menu

The Calculate menu (Fig.II.8) allows you to run the calculation on the input data.

Fig.II.8

The option Rating Curve determines the discharge of the selected river cross-section.

By selecting the option Static Calculations the program conducts the hydraulic and static checks on the channellining and filters available, according to chapter 2.2 , Part I.This option cannot be selected until the discharge value is available.

By selecting the option Waves the program will search for the lining which best counteracts wave motion. Theprogram will conduct this check even if the rating curve has not been previously calculated.


8

9.2.4. Formula Menu

The option Unit weight water allows you to modify (i.e. when the water has a non-negligible sediment transport)the water unit weight: the default values are respectively 1800 kg/m 3 and 1000 kg/m 3 .

Fig.II.9

9.2.5. Help Menu

Fig.II.10

This menu (Fig.II.10) provides the user with all information relevant to the pull down menu.

The option About Bank protection... consists of a help guide on the Bank Protection software. To enter thisoption use F1 also.

The option Project Infos.. (Fig.II.11) allows you to type in the projects name which will be printed on the outputreport. The projects name will be printed on the upper edge of the output report.

Fig.II.11


9

9.3. River bed general data (Press F1 for help)

Fig.II.12

Fig.II.12 shows the window which appears on the screen after the Maccaferri Logo is displayed. This windowallows you to type in the general input data relevant to the river bed:

Qp = design discharge;if = slope of the river bed along the cross-section analyzed.

To move from one data field to another use the TAB key. Press enter to speed up this operation once you havetyped in the required value. You can access the following window only if all input data have been provided.


10

9.4. Cross-section type selection (Press F1 for help)

Fig.II.13

Once the river bed general input data have been provided, you must select the type of river cross section.


11

9.5. Specific parameters of the cross-section (Press F1 for help)

Fig.II.14

To type in the specific parameters of the cross-section you must select the desired segment of the channel crosssection (Fig.II.14) by clicking either on that segment or on the number corresponding to that segment. Than typein the input data required (Fig.II.15).

If you mistakenly select the wrong segment, by pressing Cancel you can go back to the previous window.N.B.: you are allowed to specify the number of sub-segments (One, Two or Three) only if the general parameters ofthe cross-section have been previously provided. Conversely the program will display an error message.

When you enter this window, the program displays the default values which can be easily modified.


12

Fig.II.15

Users are required to provide the following data:

Specific parameters:

Once you have selected the geometry you must specify the specific parameters of the cross-section, in particular:

Height elevation of the lower edge of the selected segment (m), referred to the river bed;Slope slope of the selected section in terms of y/x;Length the effective (non projected) length of the segment selected (m);Coefficient of curvature multiplying factor for a bend, that is the increment coefficient of the shear stress

acting on the rivers outer bank. Refer to the reference manual for furtherinformation on the value to type in (default value = 1).

Substretches select the no. of sub-segments desired 1, 2 or 3.Velocity limit maximum admissible velocity for the granular material under the lining;Friction angle friction angle for the granular material of the stretch

Once you have completed this operation you are allowed to select the number of sub-segments by selecting therelative number (Fig.II.16):


13

Fig.II.16

An additional window relevant to the sub-segment parameters will be displayed (Fig. II.16).You must specify the sub-segment length and the type of material (Maccaferri product or BEtechnique).

Once you have provided the characteristics of the selected segment and relative sub-segments,press OK (remember that the program automatically checks the parameters of each segment whileyou are selecting the number of sub-segments and it checks the sub-segments parameters whenyou press OK to confirm your choice).

It is important to point out that the user may type in a personal material of which are knownroughness n and shear resistance tc (fig. II.17), both for Maccaferri products and Bio-Engineeringtechniques. The user may save in a single file up to 20 different types for each category ofproducts.

This opportunity allows the user to create one or more library files containing all the addedtechniques: starting from these files it is possible to design all the different cross-section types.The personal list will appear on video as shown in fig. II.18 (in this case the list is limited to 6added techniques).


14

Fig. II.17

Fig. II.18


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When you have completed typing in the parameters of a segment, the program willautomatically change it into a thicker segment: furthermore the field relevant to the number ofsegments to select will disappear.

All of these windows will also allow you to modify the input data previously provided. Byselecting a segment, the input data previously specified will be displayed.

The buttons represented in the bottom left of the screen must be used for the followingoperations: Open faucet: conducts the rating curve calculation (equivalent to the rating curve option of the

Calculation Menu); River bed: returns to the window relevant to the general parameters of the river (equivalent to

the option New Alveous of the File Menu); Cross-section: returns to the cross-section type selection (equivalent to the option New Cross-

section of the File Menu) Waves: opens the window relevant to the check against wave motion.

To make the Bank Protection software simple and quick to use, some buttons have the samefunction as the options available on the pull down menu.


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9.6. Rating curve (Press F1 for Help)Once all cross-section data has been provided, one may proceed to calculate the cross-section discharge.The output data (the water level relevant to the flood design and the average velocity acting upon the cross-

section) are shown in the windows represented in Fig. II.19 and II.20 along with the pick buttons. The bottomhalf of the screen shows a scale model of the river cross-section.

Fig. II.19


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Fig. II.20

The letters represented in the rectangles on each sub-stretch (capital letters for the Maccaferri products, smallletters for the B.E. techniques), according to their configuration allow the user to choose the most suitable materialfor the cross-section lining.

The user may move, re-design or cancel (by a double click) the legend window if it intereferes with otherwindows.

Even the print preview window may be closed with a double click.The pick buttons, starting from the left to the right and from the top to the bottom, may be used for the followingfunctions:

Data sheet: returns to the type in/modify cross-section data window; Stylized graph: plots the cross-section discharge graph. If desired, it may be closed by a double click. River: returns to the window relevant to the river general data (it is equivalent to the option New alveous on the

File Men); Cross-section: returns to the window for the selection of the cross-section type (it is equivalent to the option

New Cross-section of the File Menu); Skidding car: allows one to run the lining stability checks; Waves: activates the window to run the check against wave motion.

9.7. Lining stability checks (Press F1 for Help)Once the hydraulic calculation has been conducted, the user can run the lining stability checks. The results

of this calculation, which may be activated from the Calculation Menu or the appropriate button, can be displayedon the screen in a window as shown in Fig.II.21. If the results are not totally visible, it is possible to show them bymeans of the button placed on the right side of the results windows. The same results shown in Fig. II.21 areprovided in the file or paper report with a different layout.


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Fig.II.21

9.8. Lining design with respect to wave motion (Press F1 for Help)

Fig.II.22

Independently from the discharge calculation, it is possible to design the most suitable lining to counteract thewave motion.

The input data required are listed below (Fig.II.22):


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Input data required for the lining design against wave motion:

Hs = design wave height (m);slope = slope of the revetted area (rad);

The pick buttons (starting from the left to the right) have the following functions:

Waves: allows the design of the lining minimum thickness; Curved arrow: returns to the previous windows.

PART III - NUMERICAL EXAMPLEAll pages of the final report are shown in the following example, where many different protection types have beenused. You can consult them by entering the Es_1.dtc file supplied along with the software.

Documents

Maccaferri Channel Design Manual