Structural Concrete Staircase Design
Headway construct a detailed designed for a concrete staircase on existing slope from road side opposite work shop to stock yard area located at Vale Minerals Malaysia (VMM). Client requested Headway to design the layout with a new reinforced concrete staircase with 2m width complete with 1.2m height handrail. Furthermore, the staircase length required was 28m in length and 11m height. Headway managed to accomplish the requirement of client and produce a detailed drawings and calculation report.
Assumption Made in Preparing This Design Check Report
All design information and data are provided by the owner is deemed correct and accurate for use in this analysis and design exercise. The existing slope profile provided is deemed correct and accurate on site where the proposed staircase profile is designed based upon this information.
Design Loading & Load Combination
The staircase will serve as a foot pathway where it connects the workshop and stockyard area over an existing slope. There shall be no excessive loading and no vehicular access on this staircase.
Geotechnical Information and Design Check
As there is no latest geotechnical information available, the foundation will adopt minimum achievable compaction design value since this staircase will be seated on an existing slope, where flat surface compaction is difficult. In the design analysis exercise, safe soil bearing capacity of 25kN/m2, which will be easily achievable at site is adopted as the design value for the subgrade. A layer of 150mm thick well compacted crusher run will be seated on top of the subgrade and followed by a layer of 50mm thick lean concrete. Soil spring stiffness derived from the 25kN/m2 safe design bearing capacity is used in the computer model.
A finite element analysis has been carried out to study and analyze the structural behavior of the proposed RC staircase located on the slope. The result from the model output is then extracted and the reinforcement is designed accordingly using the design code of practice. We also suggest that an addition of approximately 25kg/m3 of Wiremix W50 (material obtained from Bekaert Shah Alam Sdn Bhd) to be included in the concrete design mix to further minimize the surface concrete crack. However, this is only our suggestion as to have a better concrete surface crack control and is usage of this material is subjected to owner decision.