Stress State of Modular Blocks with Large Door Openings

Abstract

Modular construction is a modern and efficient type of construction that has gained wide recognition in the construction industry. Limited research has been conducted on how large door openings affect the stress state of modular blocks. The present study aims to investigate the features of the stressed state of modular blocks with large door openings and the effect of size and place of the doors on the openings on the overall structural behavior of the building. Four full-scale (room-sized) modular blocks of the “lying cup” type were tested to failure under vertical loading with eccentricity simulating wind effects. The varied parameters of the specimens included concrete strength and the size of the window openings. Experimental results revealed that crack opening characteristics, main load-bearing wall deformations, horizontal deflections, and failure patterns under vertical loads are directly influenced by the small thickness and increased flexibility of the blocks. The effects of size and the placement of openings on the overall structural behavior of the building were analyzed. Tests revealed the distribution of compressive stresses in the main load-bearing walls of the “lying cup” blocks with an embedded reinforced concrete panel, considering vertical load eccentricity. Maximum compressive stresses in the longitudinal walls reached 70–80% of concrete strength, while in end walls and panel walls, they were 50–60%. Additionally, non-uniform deformations were observed in the supports of main load-bearing walls near the conjunction with the end walls and the edges of door openings. Average compressive strains in these walls were in the range of 470–500 × 10−6 , which corresponds to 22–29% of the cylindrical compressive strength of concrete. Partial factors accounting for loading conditions were introduced, allowing for further processing and the evaluation of the experimental data along with developing methods of analysis of buildings constructed with modular blocks.