Structural Performance of Sandcrete Block Walls Under Lateral Wind Loads in Coastal Communities of Rivers State

Sandcrete block walls are the dominant walling system in residential and commercial construction across Rivers State in the South South geopolitical zone, yet their structural performance under lateral wind loads specific to the coastal environment is poorly characterised. This study examines the lateral load resistance of sandcrete block walls in selected buildings within Port Harcourt and Bonny Island, where wind speeds frequently exceed those in inland regions during peak monsoon periods. Compressive strength tests were conducted on sandcrete blocks sampled from ten construction sites, and wall panel specimens were subjected to simulated lateral loading in a laboratory setting. Wind pressure calculations were derived using the Nigerian Building and Road Research Institute wind zoning classification and the provisions of BS EN 1991-1-4. Results show that the average compressive strength of locally produced sandcrete blocks was 2.1 N/mm2, significantly below the minimum recommended value of 3.5 N/mm2 specified in NIS 87. Under simulated wind loading equivalent to a 50-year return period storm, over seventy percent of unreinforced wall panels failed at lateral displacements below those permitted by serviceability criteria. The incorporation of reinforced concrete vertical stiffeners at 1.2-metre centres improved panel resistance by approximately forty-five percent. The study recommends mandatory block strength certification at coastal construction sites, adoption of reinforced masonry detailing standards, and community-level awareness programmes targeting owner-builders. Keywords: sandcrete blocks, lateral wind loads, coastal construction, Rivers State, wall performance.