Yuhang He, Rongzhuo Zhang, Yifan Zhang, Zheng Wang^*

Journal of Renewable Materials, Vol.11, No.6, pp. 2729-2743, 2023, DOI:10.32604/jrm.2023.025867

Abstract In order to better meet the objective requirements of the use safety of the high-rise glulam building floor structure and the living comfort of the residents, the transient excitation, environmental excitation and frequency spectrum identification methods were used to carry out experimental modal test in-site on the three rooms numbered A, B and C of the same glulam structural building. The three rooms have different functions, different floor sizes and different floor supporting structures. The research results have shown that the first-order bending frequency of the floor structure of Room A is 27.50 Hz, the transverse second-order bending frequency is… More > Graphic Abstract

Xiaofeng Zhang¹, Lisheng Luo^2,*, Youfu Sun¹, Xinyue Cui², Yongqiang Zhang²

Journal of Renewable Materials, Vol.11, No.4, pp. 2033-2054, 2023, DOI:10.32604/jrm.2022.023651

Abstract Considering the glulam beam-column connection form and the number of bolts, monotonic loading test and finite element analysis was carried out on 9 connection specimens in 3 groups to study the rotational performance and failure mode of the connection. The test results revealed that compared with U-shaped connectors, T-shaped connectors can effectively improve the ductility of connections, and the increase in the number of bolts can reduce the initial stiffness and ductility of connections. By theoretical analysis, formulas for calculating the initial stiffness and ultimate moment of connections were deduced. Subsequently, the moment-rotation theoretical model of connections was established based… More > Graphic Abstract

Lisheng Luo^1,*, Xinran Xie¹, Yongqiang Zhang¹, Xiaofeng Zhang², Xinyue Cui¹

Journal of Renewable Materials, Vol.11, No.2, pp. 791-809, 2023, DOI:10.32604/jrm.2022.022539

Abstract Traditional methods focus on the ultimate bending moment of glulam beams and the fracture failure of materials with defects, which usually depends on empirical parameters. There is no systematic theoretical method to predict the stiffness and shear distribution of glulam beams in elastic-plastic stage, and consequently, the failure of such glulam beams cannot be predicted effectively. To address these issues, an analytical method considering material nonlinearity was proposed for glulam beams, and the calculating equations of deflection and shear stress distribution for different failure modes were established. The proposed method was verified by experiments and numerical models under the corresponding… More > Graphic Abstract

Xiaowu Cheng, Xinyan Tao, Lu Wang^*

Journal of Renewable Materials, Vol.11, No.2, pp. 905-920, 2023, DOI:10.32604/jrm.2022.023196

Abstract This paper presents experimental and numerical investigations on progressive collapse behavior of a two-story glulam frame when the side column is exposed to ISO834 standard fire. The collapse mechanism initiated by fire is identified. The experimental results show that the progressive collapse of a glulam frame could be described for three stages, namely bending effect stage, catenary effect stage and failure stage, respectively. These stages are discussed in detail to understand the structural behavior before and during collapse. It is demonstrated that the entire frame slopes towards the side of the heated column, and the “overturning” collapse occurs eventually. The… More >

Yifei Yin, Lirong Qu, Weidong Lu^*, Chengshuai Li

Journal of Renewable Materials, Vol.10, No.6, pp. 1517-1535, 2022, DOI:10.32604/jrm.2022.018149

Abstract Creep test results of glulam members under compression and bending were studied in this paper. The creep tests were conducted to investigate the influence of the stress level and relative eccentricity on the creep deformation of glulam members. The test results showed that the creep deformation trends of glulam members under long-term compression and bending loading were similar; the creep deformation increased with increases in both the stress level and relative eccentricity. However, the relative creep deformation decreased with the increase in both the stress level and relative eccentricity under long-term loading, and a five-parameter creep model was proposed to… More > Graphic Abstract

Reza Hajihassani¹, Saman Ghahri¹, Seyedeh Masoomeh Zamani², Amir Nourbakhsh^1,*

Journal of Renewable Materials, Vol.10, No.2, pp. 511-526, 2022, DOI:10.32604/jrm.2022.017781

Abstract In this research, some practical aspects of densified wood glulam were investigated. For this aim, poplar wood specimens were densified by hygro-thermo-mechanical technique. Glulam specimens were produced by finger joint technique and polyurethane glue was used as resin. Physical and mechanical properties of glulams were investigated according to ASTM D 143-09, ASTM D 905-03 and ISO 8375 standards. Based on obtained results, using this process (steam and pressurize compaction) resulted in improvement of physical and mechanical properties of glulam specimens. Optical microscopic and scanning electron microscopic (SEM) pictures were proved structural changes on wood material during of applied technique. Generally,… More >

Nan Guo¹, Jing Ren¹, Ling Li^1,*, Yan Zhao², Mingtao Wu¹

Journal of Renewable Materials, Vol.10, No.1, pp. 183-201, 2022, DOI:10.32604/jrm.2021.015756

Abstract Due to creep characteristics of wood, long-term loading can cause a significant stress loss of steel bars in reinforced glulam beams and high long-term deflection of the beam midspan. In this study, 15 glulam beams were subjected to a 90-day long-term loading test, and the effects of long-term loading value, reinforcement ratio and prestress level on the stress of steel bars, midspan long-term deflection, and other parameters were compared and analyzed. The main conclusions drawn from this study were that the long-term deflection of the reinforced glulam beams accounted for 22.5%, 20.6%, and 18.2% of the total deflection respectively when… More >

Ruyuan Yang¹, Haitao Li^2,*, Assima Dauletbek^1,2, Mahmud Ashraf^2,4, Rodolfo Lorenzo³, Youfu Sun¹, Yuehong Wu¹

Journal of Renewable Materials, Vol.9, No.7, pp. 1293-1307, 2021, DOI:10.32604/jrm.2021.015296

Abstract This paper presents an experimental investigation to identify suitable indices to assess durability of glulam when subjected to freeze-thaw cycles in an exposed enviroenment. In this study, two types of glulam specimens were tested for their performance when subjected to different levels of aging due to freezing and thawing. Effect of aging treatment on various parameters including thickness swelling rate, static bending strength, elastic modulus, shear strength, and peeling rate of adhesive layer were studied. Obtained results showed that freeze-thaw aging treatment did not affect the water-resistance of the specimens as measured by thickness swelling rate and had little effect… More >

Nan Guo^1,*, Huajing Xiong¹, Mingtao Wu¹, Hongliang Zuo¹, Fengguo Jiang², Xiaofeng Hou³, Dabo Xin¹

Structural Durability & Health Monitoring, Vol.14, No.3, pp. 229-248, 2020, DOI:10.32604/sdhm.2020.09104

Abstract Creep is an important characteristic of bamboo and wood materials under long-term loading. This paper aims to study the long-term bending behaviour of prestressed glulam bamboo-wood beam (GBWB). For this, 14 pre-stressed GBWBs were selected and subjected to a long-term loading test for 60 days. Then, a comparative analysis was performed for the effects of pretension values, the number of pre-stressed wires, and long-term load on the stress variation of the steel wire and the long-term deflection of the beam midspan. The test results showed that with the number of prestressed wires increasing, the total stress of the steel wire… More >

Ruyuan Yang¹, Chaokun Hong², Xiaofeng Zhang¹, Quan Yuan³, Youfu Sun^1,*

Journal of Renewable Materials, Vol.8, No.2, pp. 113-132, 2020, DOI:10.32604/jrm.2020.08190

Abstract In order to enhance the bearing capacity of structural components, save materials, and reduce cost, a glued laminated timber (glulam) I-beam that is theoretically suitable for engineering application was proposed. In this study, 18 glulam specimens were fabricated using larch dimension lumber and resorcinol– formaldehyde resin. Four-point bending tests were carried out to compare the ultimate bearing capacity, strain, and deflection of various specimens. The results showed that: (1) The typical failure mode at bending is the web shear failure parallel to grain. Before the failure, cracks and sounds appear at the beam web, which represent the sudden brittle failure.… More >