43
views
0
recommends
+1 Recommend
1 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      BEHAVIOUR OF PLASTERED STRAW-BALE ASSEMBLIES SUBJECTED TO THREE-POINT BENDING

      research-article

      Read this article at

      ScienceOpenPublisher
      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          The search for more sustainable construction methods has renewed interest in straw-bale construction. Rectangular straw bales stacked in a running bond and plastered on the interior and exterior faces have been shown to have adequate strength to resist typical loads found in one- and two-storey structures. The straw bales provide excellent insulation, while possessing low embodied energy compared to conventional insulation materials.

          The structural behaviour of a load-bearing plastered straw-bale wall subject to uniform compressive loading has been the focus of a number of studies reported in the literature. However, in a typical building wall, there will be numerous locations (such as around window and door openings) where the load paths produce areas of concentrated stress. The behaviour in these regions cannot necessarily be predicted using tests from uniformly loaded wall assemblies.

          This paper describes experiments on plastered single bale assemblies subjected to three-point bending. These assemblies develop shear and flexural stresses, and so simulate the stresses that exist around door and window openings in a wall. The specimens were rendered with lime-cement plaster, and were either unreinforced, or contained steel “diamond lath” mesh embedded within the plaster. The specimens were pin-supported at various centre-to-centre distances (L) ranging from 200 mm to 500 mm. The height (H) of all specimens was constant at 330 mm. This gave a range of H/L values of 0.66 to 1.65.

          Two distinct types of failure were observed. For tests with H/L < 1, failure was due to flexural tension cracks in the plaster which propagated through the depth of the plaster skin. For tests with H/L > 1, failure was due to crushing of the plaster in compression under one of the loading points.

          It was shown that models based on simple mechanics were able to adequately predict the assembly strength. In particular, analysing the assemblies with H/L < 1 as simple beams, and using the transformed section concept to deal with the straw and steel mesh, was adequate for predicting their strength.

          The results suggest that current practice for straw bale construction is generally appropriate. To avoid tensile cracking of plaster due to flexure, regions around doors, windows, and other openings should be designed such that H/L > 1. In regions where H/L < 1, the use of steel reinforcing mesh can increase the plastered bale strength by 30% on average.

          Related collections

          Most cited references2

          • Record: found
          • Abstract: found
          • Article: found
          Is Open Access

          COMPRESSIVE TESTING AND ANALYSIS OF PLASTERED STRAW BALES

          The structural performance of plastered straw bales under compressive loading is extremely important when considering the suitability of plastered straw bales as a construction material. Most currently available results do not investigate how different construction methods and practices can affect the strength of a plastered bale. The experiments discussed in this paper illustrate how the strength of the plaster, the thickness of the plaster and the orientation of the bale itself can affect the strength of the plastered bale. It was found that the bales plastered flat were 36% stronger than those plastered on edge. In addition it was found that although the plaster strength does affect the strength of the plastered bale, it does not have as significant an impact as the plaster thickness. It was also found that nearly all plastered bales tested had higher strengths than would be required in typical residential construction. The strengths were found to be in the same range as the values reported in the existing literature. The plastered bale modulus was found to be highly variable and un-predictable.
            Bookmark
            • Record: found
            • Abstract: found
            • Article: found
            Is Open Access

            RECOMMENDED MESH ANCHORAGE DETAILS FOR STRAW BALE WALLS

            Experimental studies on full-scale straw-bale walls have demonstrated the adequacy of straw-bale wall systems for resisting lateral loads from wind or seismic actions. Critical to the performance of the wall system is the anchorage of mesh reinforcement to the bottom plate and to the roof bearing assembly or top plate. Reported in this paper are the results of experiments examining mesh strength, anchorage strength, and failure mode for a variety of reinforcement meshes (steel, plastic, and hemp) and anchorage details. Because of the potential for new wood preservative pressure treatments to cause corrosion, stainless steel staples driven pneumatically into pressure-treated sill plates were tested in addition to electro-galvanized staples driven pneumatically into untreated sill plates and a heavier gauge staple driven manually into an untreated sill plate. Recommended anchorage details are identified, considering not only the test results but also the many other factors that must be considered in developing reliable, economical, and constructible details.
              Bookmark

              Author and article information

              Journal
              jgrb
              Journal of Green Building
              College Publishing
              1552-6100
              1943-4618
              1943-4618
              Summer 2012
              : 7
              : 3
              : 95-113
              Author notes

              1Junior Engineer, Kiewit-Alarie, Kapuskasing, Ontario, Canada, mr.rakowski@ 123456kiewit.com

              2Associate Professor, Department of Civil Engineering, Queen's University, Kingston, Ontario, Canada, colin@ 123456civil.queensu.ca

              Article
              jgb.7.3.95
              10.3992/jgb.7.3.95
              fb45f120-5a7b-4126-8ed6-29d62bc24f5e
              © 2012 College Publishing

              Volumes 1-7 of JOGB are open access and do not require permission for use, though proper citation should be given. To view the licenses, visit https://creativecommons.org/licenses/by-nc/4.0/

              History
              Page count
              Pages: 19
              Categories
              RESEARCH ARTICLES

              Urban design & Planning,Civil engineering,Environmental management, Policy & Planning,Architecture,Environmental engineering
              discontinuous regions,structural testing,3-point bending,cement-lime plaster,straw bale construction

              Comments

              Comment on this article