Comparative study of lightweight and conventional concrete materials in buildings on weak soil of coastal region in KSA

The design of RC buildings is always considered a challenge to satisfy all code life-safety requirements, to achieve sustainable performance and to economize the cost using locally available natural and artificial lightweight material. Using three different types of concrete materials (Normal concrete, Lightweight Scoria concrete, and Lightweight Polystyrene concrete), a 5-stories building, has been designed three times to allow comparing the three different materials. The building is located at the coastal area of Dammam city, Saudi Arabia. The coastal area has mostly reclaimed sites that have layers of backfill with fluctuating salty-ground water table. Where the construction sites in this region, are generally recognized as weak soil locations with low bearing capacity. Therefore, using lightweight concrete could be an effective design option minimizing the bearing loads on the soil. The design is carried out using Saudi Building Code, SBC 301 [1] and American Standards, ASCE 7-22 [2]. The structure was designed to resist gravitational loads as Dammam city is low-seismic zone. The impact of using different concrete materials on the required steel reinforcement and the total weight of the building is examined. Finally, cost analysis for superstructure and substructure has been performed to estimate the total cost of different types of concrete components of the project. Significant reduction in the steel and concrete volume LWC might be possible in the multi-storied building. It is postulated that the cost-effective and eco-friendly LWC will promote the usage of especially scoria as an effective alternative for superstructure construction.