Unit 7 Structural Flooring Systems - trentglobal.edu.sg grid of beams deeper than slab isrequired. ... Horizontal service distribution more difficult in twodirections. ... dead load

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Unit 7

Structural

Flooring

Systems

Structural Flooring Systems

Objectives

� Introduction to various flooring systems

� Advantages and Disadvantages

� Structural depth

� Cost comparison

Classification

�Conventional RC slab and beam.

�Post-tensioned slab.

�Pre-cast slab.

�Composite steel deck slab.


DROP BEAM AND SLAB

Range of Span(m)

Range of structural depth(mm)

Range of slabthickness (mm)

4 - 10 400 - 650 175 - 300

Range of cost(Dhs./m2)

197 - 345


SECTION THROUGH BEAM


Advantages

� Large openings can be accommodated in the slab

elements.

� Simpler reinforcement arrangement.

� Inherent corrosion protection and fire resistance.

� Traditional method of construction.

� Simple method of construction.

� Robust construction

BAND BEAM AND SLAB

Range of Span (m)

Range of structural depth (mm)

Range of slab thickness (mm)

4 - 10 300 - 550 175 - 300

Range of cost (Dhs./m2)

197 - 345


SECTION THROUGH BEAM


� Large openings can be accommodated in the slab

elements.

� Shallow depth of beams provides flexibility in

horizontal service distribution.

� Simpler reinforcement arrangement.




� Robust construction

Advantages

Disadvantages

� Large openings cannot be accommodated easily

on the beam lines.

� More complex formwork compared to flat slab

systems.

Range of Span (m)



4 - 6 180 - 250 180 - 250

FLAT SLAB


228 - 298


SECTION THROUGH SLAB


Advantages

� Flat soffit.

� Shallow depth.

� False ceiling area can be minimised.

� Flexibility in horizontal service distribution.

� Minimal site coordination

� Very simple formwork.



� Robust construction.

Disadvantages

� Vertical risers need to be pre-planned.

� Large openings near columns difficult to accommodate.

� Heavier construction than slab and beam system.

� Large amounts of reinforcements.

FLAT SLAB WITH DROP PANELS

Range of Span (m)



6 - 8 350 - 490 200 - 280


239 - 309


Advantages

� Shallow depth.

� Minimal site coordination





� Lighter construction compared to flat slab..

Disadvantages

� Drop panel makes formwork more complex.



� Heavier construction than slab and beam system.

� Large amounts of reinforcements.

RIB SLAB

Range of Span (m)

6 - 12


400 - 500


275 - 500


248 - 357

L-SECTION THROUGH

RIB SLABX-SECTION THROUGH

RIB SLAB

Advantages

� Profile may be expressed architecturally.

� Level rib and beam soffits.


� Flexibility in vertical service distribution as large

openings can be accommodated in the slab elements

between ribs.

� Lightweight construction.



� Traditional method of construction

Disadvantages

� Higher formwork cost.


on the beam lines.

� Slower construction due to increased formwork.

� Additional efforts to place reinforcements.

Range of Span (m)



7 - 13 400 - 550 300 - 550


336 - 440

RIB SLAB WITH HOURDI BLOCKS

X-SECTION THROUGH

HOURDI SLAB

L-SECTION THROUGH

HOURDI SLAB





between ribs.


� Simplified formwork compared to rib slab.



� Traditional method of construction

Advantages

� Large openings cannot be accommodated easily on the beamlines.

� Heavier compared to rib slab.

� Additional efforts to place reinforcements.

� Additional effort to place void formers.

Disadvantages

Range of Span (m)



7 - 13 400 - 650 275 - 500

WAFFLE SLAB


300 - 456

X-SECTION THROUGH

WAFFLE SLAB

Advantages

� Profile may be expressed architecturally.





between ribs.





Disadvantages

� Complex formwork required.

� Higher formwork cost than rib slab.

� Large openings cannot be accommodated easily on the

beam lines.

� Slower construction due to increased formwork.

� Difficult to prefabricate reinforcements.

POST-TENSIONED SLAB

Range of Span (m)



6 - 12 180 - 360 180 - 360


216 - 410


Advantages

� Shallow structural depth compared to solid slab.


� Flexibility for services.

� Fastest in-situ concrete option.

� Very simple formwork.

� Lightly reinforced with simple reinforcement

arrangement.



Disadvantages

� Less flexible for future modifications.

� Will require coordination with a specialist sub-

contractor on site.


� Large openings near columns difficult to

accommodate.

� Possible hindrance to the advanced

construction of shear walls.

POST-TENSIONED SLAB WITH BAND BEAMS

Range of Span (m)



7 - 12 315 - 525 180 - 300


217 - 333

SECTION THROUGH BAND BEAM

Advantages

� Shallower slab thickness.


arrangement.



Disadvantages

� Less flexibility for services due to the presence of

band beams.




on the beam lines.


contractor on site.

� Possible hindrance to the advanced construction of

shear walls.

POST-TENSIONED SLAB WITH DROP PANELS

Range of Span (m)



7 - 13 350 - 650 180 - 340


222 - 398


Advantages

� Shallower slab thickness.


arrangement.



Disadvantages

� Drop panel makes formwork more complex.

� Less flexibility for services due to the presence of drop

panels.



contractor on site.

� Possible hindrance to the advanced construction of

shear walls.



HOLLOW CORE SLAB

Range of Span (m)

4 - 15


500 - 900


220 - 270


215 - 330

SECTION THROUGH HCS SECTION THROUGH BEAM

Advantages

� Reduced structural depth.

� Flexibility for horizontal services in one direction.

� Speed of construction as much of floor system is

pre- cast in factory.

� No slab formwork.

� No slab propping.

� Lighter floor than the conventional construction.

Disadvantages� Less suitable for irregular architectural plan forms.

� A grid of beams deeper than slab is required.

� Large openings more difficult to accommodate into the slabs.

� Horizontal service distribution more difficult in two directions.

� Suspension of heavier service equipment requires co-ordination.

� As the pre-cast slab comes with a camber, levelling of the slab needs attention.

� Complications of placing the nibs on shear walls.

� Limited number of pre-cast suppliers resulting in possiblecost fluctuations.

� Requires more craneage.

EP SLAB

Range of Span(m)

4 - 12


500 - 850


270 - 470


245 - 347

X-SECTION THROUGH EP SLABL-SECTION THROUGH

EP SLAB

Advantages� More suitable for irregular architectural plan forms than

hollow core slabs.



� Larger openings can be accommodated into the slabs.

� Services can be run through void former in one

direction.

� Flexibility for horizontal services in one direction.

� Speed of construction as much of floor system is pre-

cast in factory.



� Lighter floor than the conventional construction or

hollow core.

Disadvantages

� Horizontal service distribution more difficult in two

directions.

� A grid of beams deeper than slab is required.

� Suspension of heavier service equipments

requires coordination.

� As the pre-cast slab comes with a camber, levelling

of the slab needs attention.


� Limited number of pre-cast suppliers resulting in

possible cost fluctuations.


Range of Span(m)



9 - 16 750 - 900 535 - 785

T – SECTION SLAB


344 - 420

X-SECTION THROUGH SLABL-SECTION THROUGH SLAB

Advantages


� Flexibility for horizontal services in both directions as

concealed nibs can be used to support the pre-cast

slabs.



between ribs.

� Smaller horizontal penetrations can be pre-cast in the

ribs.

� Speed of construction as much of floor system is pre-

cast in factory.



� Lighter floor than the conventional construction.

Disadvantages

� Less suitable for irregular architectural plan forms.

� Large openings more difficult to accommodate into the

slabs.

� Suspension of heavier service equipments

requires coordination.

� As the pre-cast slab comes with a camber, levelling

of the slab needs attention.


� Limited number of pre-cast suppliers resulting in

possible cost fluctuations.


COMPOSITE DECK SLAB ON STEEL BEAMS

Range of Span (m)

4 - 10


376 - 737


323 - 587


461 - 1093

SECTION THROUGH

SECONDARY BEAM

SECTION THROUGH

MAIN BEAM

Advantages


openings can

be accommodated between the secondary steel

beams.

� Compatible with possible large span steel transfer

structures.

� Rapid construction.



� This is the lightest option resulting in smaller

columns and foundations

Disadvantages

� Horizontal service distribution more difficult.

� Greater floor depth compared to other systems.

� Could require longer lead-time depending on

availability of steel sections locally.

� The steel beams will require additional corrosion

resistance and fire protection.

� Greater cost

� Spans of 4.0 m to 16.0 m are considered for analysis.

� Beam spans are limited to 9.0 m.

� A typical office floor loading of 3.5 kN/m2 super imposed

dead load and 4.0 kN/m2 live load is considered.

� Cost of structural elements and fire proofing only are

included in the total cost.

� Indirect costs are not included in the total cost.

Comparison of Slab systems

Assumptions

Documents

Unit 7 Structural Flooring Systems - trentglobal.edu.sg grid of beams deeper than slab isrequired. ... Horizontal service distribution more difficult in twodirections. ... dead load