Tech Spec I - Steel Structure_RGHEP

8/10/2019 Tech Spec I - Steel Structure_RGHEP

http://slidepdf.com/reader/full/tech-spec-i-steel-structurerghep 1/9















RASUWAGADHI HYDROPOWER CO. LTD.

Kathmandu

Nepal

LOT 1 - CIVIL AND HYDROMECHANICAL WORKS

Bid

Documents:

Volume 3 - Part

IV

Employer s Requirements

ASUWAGADHI HEP

15

15.1

(a)

b)

15.2

(a)

(b)

(c)

(d)

15.3

(a)

b)

(c)

(d)

15 4

(a)

PERM NENT BRIDGES

Function

The

main public road providing access to the Project site (from Syabrubesi to

Rasuwagadhi) is located on the left bank of the Bhotekoshi River. The headworks

and powerhouse sites of the Project are located on the right bank. Accordingly,

construction of two bridges crossing the river, one near

to

the intake site and the

other

near

the

powerhouse site, is necessary to establish permanent vehicular

access

to

the headworks and powerhouse sites.

In addition

to

the construction of these two permanent bridge structures, it is

envisaged that the

Contractor will also need to establish temporary bridge access

across the river. The Contractor s programme, method statements and Bid Price

shall include

for

the design, construction and maintenance up to completion of the

Contract of all temporary and permanent bridges.

Employer s Concept for Bridge at Intake Site

The

Intake Bridge is a steel truss superstructure with a reinforced concrete deck

slab of single carriageway width of 4.25m without footpaths. The total width of the

bridge is 5.0m.

The

bridge abutments on both banks

of

the river comprise of reinforced concrete

cantilever abutment stem, abutment cap, reinforced concrete all and wingwalls. The

reinforced concrete backwall will be constructed monolithically with the abutment.

The

heights of the abutments shall be equal.

Approach slabs are provided behind each abutment for smooth movement of traffic

to the bridge.

The

proposed location

of

the Intake Bridge is shown in the Employer s Concept

Drawings.

Employer s

Concept for

Bridge

at Powerhouse Site

The

Powerhouse Bridge is a steel truss superstructure with a reinforced concrete

deck

slab of single carriageway width of 4.25m without footpaths.

The

total width of

the bridge is 5.0m.

The

bridge abutments on both banks of the river comprise of reinforced concrete

cantilever abutment stem, abutment cap, reinforced concrete all and wingwalls. The

reinforced concrete backwall will be constructed monolithically with the abutment.

Approach slabs are provided behind each abutment for smooth movement of traffic

to the bridge.

The

proposed location of the Powerhouse Bridge is shown in the Employer s

Concept Drawings.

Contractor s Design

The O l l o w i ~ ; ; - ( ~ ~ r r l 1 e n t s

shall be applied to both the Intake

P o w e r h o u ~ e " B J ' : ' g e , .

{ : ; / ~ , : : : , - - , = : : , - : < -

}

'::, ,



RASUWAGADHI HYDROPOWER CO. LTD.

Kathmandu Nepal

LOT 1 - CIVIL AND HYDROMECHANICAL WORKS

Bid Documents: Volume 3 - Part IV

Employer's

Requirements

ASUWAGADHI HEP

(b) The selection of the bridge sites shall be confirmed by the Contractor and approved

by the Employer. The bridge axis shall be aligned along a straight reach

of

the river

and perpendicular to the direction of flow. The abutments shall be sited on finm

riverbanks.

(c) The design and construction of the permanent bridges shall comply to 8S5400:

Steel,

concrete and composite bridges and associated standards. The bridges shall

be designed for HB45 and H loading in accordance with 8S5400.

(d) The bridges shall be designed for the 1 in 100 year flood discharges in the

8hotekoshi river with sufficient freeboard. The bridge abutments and foundations,

shall be protected, as necessary, against scour.

(e) The permanent bridges shall be designed for seismic loading.

(f) The permanent bridges shall be designed as single span stnuctures; use of

intermediate pier supports shall not be permitted.

(g) Notwithstanding the aforementioned requirements, the Contractor may propose a

steel or concrete type bridge for the permanent structures.

(h) Without prejudice to the requirements of 8S5400, all stnuctural steelwork for bridges

shall comply with Section 11

of

the General Technical Requirements. Similarly, all

concrete for bridges shall comply with Sections 8 9 and 10

of

the General Technical

Requirements, as appropriate.

(i) The bridge deck shall have a parapet and guard rails

in

accordance with 8S5400.

(j)

The bridge deck design shall be incorporate surface drainage. The carriageway

shall be provided with a 2 cross slope and rain inlets provided at 5.0m intervals. A

slight slope

of

0.6 to 1 shall be provided between the rain inlets. The pipe from

the rain inlet to discharge the water shall not be less that 200mm below the soffit of

the deck slab.

(k) The bridge bearings shall be PTFE Pot type conforming to the requirements of

8S5400.

(I) Expansion joints shall be provided at the junction of the approach slab and the

bridge deck and shall conform to the requirements

of

BS5400.

(m) Adequate river training works shall be designed and provided by the Contractor as

the site condition.

6

DISPOSAL AREA

(a) Disposal area shall be used for the disposal of excavated materials not to be utilized

for fills, backfills and aggregates. Disposal area shall

be

cleared

of

all downed and

standing vegetation and gnubbed, and topsoil shall be removed prior to placing

waste excavated materials thereon. And the drainage layers and/or drainage

trenches shall be provided.

(b)

e

SMEC

Retaining walls shall also be provided as necessary to maintain sloPEil.stability and

protection against flood

if

the area is near Bhotekoshi river or it branches. .

r i / ~ ~ ~ ~ . s \ Y