Laboratory Investigations into the Bearing Capacity of Straw Bales for Low-Rise Building Applications

Baozhu Cao,Jun Hu,Yuansong Sun,Hongxin Nie,Yingzi Yang

doi:10.1155/2021/5557040

Abstract

Investigations were carried out to study the mechanical performance under uniaxial load of unplastered and plastered straw bales. Results from tests on 30 rice straw bales indicated nonlinear load-bearing properties with large deformations and anisotropy. Since the deformations observed did not conform to the current building code requirements, the evaluation of ultimate bearing capacity through the maximum axial vertical load was not possible. To obtain the design strength of rice straw bales in composite walls, further 21 specimens of plastered straw bales were also tested in compression. The permissible deformation of the straw bales was evaluated. It is noteworthy that the large deformability of straw bales can reduce the damage to structures after an earthquake. Consequently, the straw bale use can widely enhance the seismic performance of low-rise buildings.

Highlights

E aforementioned research achievements can provide better supportive references for design and construction of straw bale structures, their application is still empirical as currently available information is limited
The unplastered straw bales displayed a nonlinear mechanical performance, making it unfeasible to establish either a bearing capacity or an elastic modulus reliably. e bearing capacity of straw bales was determined using the load sustained at a vertical displacement of 1/3 of initial block height. e elastic modulus was calculated using the stressstrain curves observed for straw bales
On comparing the tests on plastered bales with unplastered bales, it was shown that using plaster improved the load-bearing capacity of the straw bales. e maximum vertical displacement observed for straw bales in the tests was beyond 40 mm, whereas the cement plaster layer was destroyed at displacements no more than 5 mm. erefore, the bearing capacity of straw bales could be insufficient, if and when the plaster is compressed to failure

Summary

Introduction

E aforementioned research achievements can provide better supportive references for design and construction of straw bale structures, their application is still empirical as currently available information is limited. There may be wide differences in the properties of straw obtained from different areas or climates. Is paper presents a laboratory study on the behavior of 30 straw bales and 21 plastered straw bales measuring their stiffness moduli from their respective stress-strain curves. E permissible deformation of straw bales was observed together with the contribution from the cement plaster was evaluated. E specimens for testing used rice straw harvested from Jilin province in China, and the straw bales were manufactured using a hydraulic machine

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Results

Discussion

Conclusion