Structural Analysis and Design Report
Project:
Aug. 2020
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Preview:
Pursuant to the request from the representative of the above-mentioned Project to ESD to
conduct a structural analysis and design review to their concrete building, ESD carried out
a comprehensive structural redesign and check to the existing structural elements and
foundations using the as built drawing and concrete compression test results.
Scope of Work:
The purpose of the study is to investigate the presence of ultimate confidence in the safety
and adequacy of the structural elements’ capacity of buildings and the maximum ultimate
design loads the building can carry using the reduced concrete strength, and to check the
capability of the structure to safety transfer the additional loads of a new floor to the
foundations.
Methodology:
The building was modelled according to the as built drawings, all dimensions were checked
for consistency, and reinforcement stated in the drawings was entered in the ETABS model.
Material property was collected and defined to the model elements and members according
to what has been stated in the drawings. British Standards Spread sheets and ETABS and
SAFE software were used for analysis and design.
Specifications, standards and programs
1. BS 8110-97 for design and verifications of the results.
2. BS 6399 Part 1 for Dead and Live load.
3. BS 6399 Part 2 for Wind load.
4. ETABS 2018.
Method of Analysis and Loading
Structural behavior of the system was captured through a complete three-dimensional
model of structural analysis by using ETABS. Finite elements method is the tool that the
program uses during the analysis. The design loads used to analyze the building are adopted
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in accordance with the BS6399 considering material properties and building utilization.
Load combinations for design assessment purposes were chosen according to BS 8110-97.
Ultimate load combination was used.
Loads Considered:
The building was checked according to following types of loads:
1. Dead load of 1.2 kN/m2 as finishes (Sand bedding, Ceramic and 4.5 cm mortar).
2. Self-weight of the structure.
3. Walls as 11.5 kN/m for 2.55 m height wall of 25cm thickness.
4. 6.75 kN/m for Parapet wall of 25cm thickness using brick density of 18.0 kN/m3.
5. Live load of 3.0 kN/m2 on stair and lobbies.
6. Live load of 1.5 kN/m2 for domestic.
7. Wind speed was assumed to be 30 m/s.
8. Concrete density 24 kN/m3 and gravitational acceleration 9.81 m/s2.
Materials Properties:
Concrete:
Columns: Fcu = 16 MPa
Foundations: Fcu = 20 MPa
Slabs: Fcu = 16 MPa
Steel for Reinforcement:
The steel used is: Grade 460 MPa.
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Design Outputs and Recommendations:
Problems:
1. The concrete cores’ test shows that the concrete strength of RC members
is relatively low as mentioned above.
Outputs:
1- All the concrete members passed the design check.
2- The columns can withstand the load of the existing floors.
3- Foundations can carry the load of the existing floors and transfer it safely
to the underneath soil.
4- There no problem in the structural capacity of footings (shear + flexural).
5- The bearing pressure under foundations is less than 200 KN/m2
for all footings.
6- The building, however, cannot withstand the load of an
additional new floor.
7- The old columns can withstand the additional load from the
building expansion.
Recommendations:
1. If an addition of a new floor is requested, some RC columns must be strengthened
by increasing the cross-sectional area (e.g. Concrete jacketing).
2. The ground floor expansion, as shown in MMC proposal, would require
construction of new footing foundations, grade beams and slab expansion.
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