The bending properties of bamboo bundle laminated veneer lumber (BLVL) double beams Fuming Chen a , Zehui Jiang a , Ge Wang a,⇑ , Haidong Li a , Lee M. Simth b , Sheldon Q. Shi b a International Centre for Bamboo and Rattan, Beijing 100102, China b Mechanical and Energy Engineering, University of North Texas, Denton, TX 76203-1277, USA highlights  Large span bamboo bundle laminated veneer lumbers (BLVLs) were prepared by combining the prepress densification process.  Mechanical performances of the intermittent hot joints and adjacent positions of large span BLVLs were investigated.  A new type of BLVL double-beam members was developed and their bending properties including ultimate load, static bending strength and strain distribution were systematically analyzed. article info Article history: Received 7 November 2015 Received in revised form 6 March 2016 Accepted 20 March 2016 Keywords: Bamboo bundles Intermittent hot press process Laminated veneer lumber (LVL) Double beams Mechanical properties abstract Large span bamboo bundle laminated veneer lumbers (BLVLs) were prepared by combining the prepress densification process and the intermittent hot press process. Their mechanical performances of the inter- mittent hot joints and adjacent positions were also investigated. Based on this, a new type of BLVL double-beam members was developed and their bending properties including ultimate load, static bend- ing strength and strain distribution were systematically analyzed by comparing with other double beams with different members. The results showed that large span BLVLs could be well prepared by intermittent hot press process and its mechanical properties could meet the requirements of 160-E superior products according to Chinese national standard GB/T 17657-2013. Besides, the values for the cross-section flex- ural rigidity and bending modulus of BLVL double beams were extremely high. Bamboo-wood composites (BWC) double beams with more ductility coefficient had a great ability of plastic deformation. For these double beams, the cross-section stiffness was the first factor which to be considered and optimized and the change of the strain along thickness direction was linear, which was in line with the hypothesis the- ory of bending plane of materials. This study was finally beneficial to design, manufacture, and applica- tion of bamboo-based structural engineering materials with lightweight, low cost, and excellent mechanical performances by supplying financial data support. Ó 2016 Published by Elsevier Ltd. 1. Introduction Environmental conservation and wood-based resource short- ages have promoted worldly attention to abundant bamboo resources as a favored and sustainable building material due to its fast growth, environmental friendliness, capability of reuse, and its excellent mechanical properties comparative with those of structural wood products [1–5]. Bamboo-based construction engineering materials like beams, roof truss, and wall elements of residential houses has been extensively applied and further investigated. These investigations are looking into innovative products with desired mechanical and physical performances and upgrading process technologies [6–11]. In order to sufficiently take advantage of abundant sympodial bamboo resources, a lot of bamboo-based composites with well designed structures have been developed [11–14]. Bamboo bundle laminated veneer lumbers (BLVLs), which were manufactured by arranging rolled and broomed bamboo bundles and hot-pressing, are a potential construction engineering composite due to its favorable density uniformity, dimensional stability, and stability of mechanical performances [15,16]. The limitation of BLVLs’ size has hindered its further success as a long-span structural compo- nent like beams due to the lack of continuous hot pressing machinery. Large investments and lack of proper equipment and technologies have promoted researchers’ attention to be http://dx.doi.org/10.1016/j.conbuildmat.2016.03.114 0950-0618/Ó 2016 Published by Elsevier Ltd. ⇑ Corresponding author. E-mail address: wangge@icbr.ac.cn (G. Wang). Construction and Building Materials 119 (2016) 145–151 Contents lists available at ScienceDirect Construction and Building Materials journal homepage: www.elsevier.com/locate/conbuildmat