Research on dynamic characteristics test of wooden floor structure for gymnasium

In order to better evaluate the structural performance of the wooden floor used in the gymnasium and realize the structural optimization design, this research considered two gymnasium’s floors in Nanjing as the research object and used the transient excitation method to test the natural frequency and damping ratio parameters of the three types of floor structures. The results showed that three kinds of floor structures all meet the requirements of building comfort; under the premise that the types and specifications of the constituent materials were the same, the order of the damping ratios of the three kinds of floor structures from large to small was: the fixed floor structure with double-layer load distribution strip, the suspended floor structure with single-layer load distribution strip, and the suspended floor structure with double-layer load distribution strip; compared with the fixed floor structure, the suspended floor structure had low damping ratio characteristics, the energy dissipation was slow during structural vibration, which means its impact absorption rate was small, and its impact buffering ability was good. The integral structure had good resilience performance; compared with the floor structure using single-layer load distribution strip. The floor structure using a double-layer load distribution strip had a low damping ratio characteristic. The absorption rate of the structure was small and the resilience performance was good. The research conclusion had certain engineering application value.

A review of mechanical behavior of structural laminated bamboo lumber

The transition of the construction sector to sustainable development mostly depends on the environmental friendliness of building materials. This, in turn, calls for the development of new, strong, and sustainable materials that would be a worthy alternative for traditional materials, including wood. Over the past decade, laminated bamboo lumber (LBL) has received much attention from engineers, practitioners, and scientists for its attractive mechanical properties, comparable to and in some cases superior to hard and softwood. Moreover, the sustainability of LBL is characterized by its high carbon sequestration, fast time to harvest, high yield, and low energy consumption for processing. However, the behavior of LBL is not yet fully understood, which in turn affects the low awareness and application of the material by practitioners and engineers around the world. Since LBL has a promising future, this article will contribute to a better understanding of its mechanical properties and a more accurate design, taking into account the influencing factors. This article discusses the mechanical properties of three types of structural LBL, namely beams, columns, and sheathing panels. The previous works of researchers on the mechanical properties of structural LBL were reviewed, and thus the most common failure modes, the causes of the destruction of structural elements, and the factors that affect their behavior were discussed and described. This work will serve as a reference for current practitioners and future research.

Material characterization and structural response under earthquake loads of hakka rammed earth buildings

Hakka Tulou are rammed earth buildings that have survived material aging, natural weathering and earthquakes for hundreds of years. Previous paper has reported our observations and findings from nondestructive evaluations in field with focus on the integrity of the rammed earth outer walls and inner timber structures as well as the thermal comfort of living in these buildings [1]. This paper presents the structural response of Tulou buildings under earthquake loads using material data from field and employing finite element (FE) analysis program. The material characterization included scanning electron microscopy and compression strength/modulus of rammed earth samples and wall reinforcements, revealing their high strength and durability. The FE analyses were conducted on unreinforced Huanji Tulou as per the simplified lateral force analysis procedure defined by the Code ASCE-7 under three types of wall conditions: 1) unreinforced rammed earth outer wall only, 2) reinforced rammed earth outer wall without inner wooden structures, and 3) unreinforced rammed earth outer wall with inner wooden structures. The FE modeling revealed that the existing large crack in the outer earth wall of Huanji Tulou would not have developed under a strong earthquake load if the earth walls were reinforced. Furthermore, the high volume rammed earth wall integrated with inner timber structures would have offered the building unique earthquake resistance.

Semi-rigid behaviour of stainless steel beam-to-column bolted connections

Stainless steel is increasingly used in structural applications but there is still significant lack of experimental evidence on the moment-rotation (M-) behaviour of moment resisting beam-to-column connections. The current paper presents experimental test results obtained from full scale tests conducted on three widely used connection types i.e., double web angle (DWA), top seat angle (TSA) and top seat with double web angle (TS-DWA) connection. Considered beam, column and angle sections were fabricated using austenitic stainless steel plates and M20 high strength bolts were used for connection assembly. M- curves for all connections were carefully recorded and were used to determine initial stiffness (Ki) and moment capacity (M20mrad) for each of the connections. Eurocode 3 guidelines were used to check the classification i.e., whether or not the connections were semi-rigid in nature. Although the considered DWA connection failed to achieve partial-strength, both TSA and TS-DWA connections showed obvious semi-rigid nature despite the connection capacities were limited by bolts. In addition, extensive ductility of stainless steel ensured that all three connection types achieved a minimum connection rotation of 30 mrad, which is specified by FEMA as a requirement for earthquake design of ordinary moment frames.

Design issues for smart isolation of structures: past and recent research

The paper focuses on a number of original researches developed by the authors concerned with the development of new design approaches for smart base isolation systems for structures. Base Isolation (BI) systems represent the first kind of control devices applied to civil structures. In the paper, advancement in technology is exploited in this field, allowing to conceive new BI typologies possibly based on the adoption of special smart materials or on the coupling of the basic passive device with additional corrective devices, in such a way to minimize the disadvantages deriving from the simply passive system. Illustrated procedures also embed in the design pattern of base-isolation systems the interaction effects between structure and soil in order to provide the best tuning of the isolation parameters and to get the maximum performance of the devices, finally summarizing a number of original approaches to design under passive, semi-active and hybrid modes.

Experimental estimation of energy dissipated by multistorey post-tensioned timber framed buildings with anti-seismic dissipative devices

The need to satisfy high seismic performance of structures and to comply with the latest worldwide policies of environmental sustainability is leading engineers and researchers to higher interest in timber buildings. A post-tensioned timber frame specimen was tested at the structural laboratory of the University of Basilicata in Italy, in three different configurations: i) without dissipation (post-tensioning only-F configuration); ii) with dissipative angles (DF- dissipative rocking configuration) and iii) with dissipative bracing systems (BF - braced frame configuration). The shaking table tests were performed considering a set of spectra-compatible seismic inputs at different seismic intensities. This paper describes the experimental estimation of energy dissipated by multistorey post-tensioned timber prototype frame with different anti-seismic hysteretic dissipative devices used in the DF and BF testing configurations. The main experimental seismic key parameters have also been investigated in all testing configurations.

Structural design and construction of an office building with laminated bamboo lumber

With so many advantages such as environmental friendliness, fast-growing, high strength-to-weight ratio, sustainability, and the capability of being reused or recycled, bamboo structures has gained more and more attention for scientists. This paper shows the feasibility of the design of an office building using laminated bamboo lumbers in compliance with the Chinese standards as GB50009-2012, GB50011-2010, GB50016-2014, and GB 50005-2017. Detailed information about the materials and building were offered. A lot of related construction photos were offer to show the building process. This case is a very good application example for laminated bamboo lumber buildings and has attracted many engineers’ attention in industrial field. Laminated bamboo lumber structures should have a bright future. It should become one main structure form in civil engineering area. However, due to none existing engineered bamboo structures design standard now, engineers have to take reference to standards for timber structures. Setting up the standard system is very important for engineered bamboo structures’ application. Through more and more scientists’ hard working, it might be not a long way to build the code system.

3D printed concrete components and structures: an overview

This paper aims to present an overview and explore components or structures suitable for 3D printed concrete. Most traditional structural forms are not well suitable for 3D printed concrete. To be more specific, it cannot fully consider the characteristics and advantages of 3D printing such as individualization and digitalization. Several 3D-printing-specific structure forms (including hollow form, tree form, arch form, and structure-functional form) are classified and the relevant successful cases are demonstrated. Moreover, the application potential of 3D printed concrete structures is illustrated and the limitations as well as the solutions for the application of 3D printed concrete in practical projects are also summarized. Based on the classification of different reinforcement materials, several reinforcement methods are intensively discussed for 3D printed concrete including steel bars, fibers and other reinforcement materials. The comparison of economic and environmental benefits between 3D concrete printing technology and traditional construction method is discussed respectively. Finally, the expected evolution of 3D printed structures is put forward and recommended.

Review on mechanical behavior of solar cells for building integrated photovoltaics

The energy crisis and environmental pollution have promoted the rapid development of renewable solar technology. Building integrated photovoltaics (BIPV) is an important field for the future development of solar energy. This review presents the mechanical property studies of existing BIPV and analyzes its research status to offer advice for engineering applications. By analyzing the types and mechanical characteristics of solar cells in the existing BIPV and determining the load conditions that need to be considered in different application modes, this paper summarizes the relevant existing studies at the photovoltaic material, cell and component levels and offers corresponding suggestions for mechanical research, which consequently results in the proposal of a new BIPV structure. Since the mechanical properties of BIPV have seldom been studied, and research on practical engineering applications is lacking, further comprehensive and in-depth research is needed to promote the safe and reliable application and popularization of photovoltaic building integration.

Development and evaluation of load-bearing fiber reinforced polymer composite panel systems with tongue and groove joints

This paper focuses on recent advances made in design, development, manufacturing, evaluation and modeling of load bearing fiber reinforced polymer (FRP) composite sandwich panel systems including tongue and groove joints. Several processes have been researched in collaboration with industry partners for production of composite panels, including: 1) pultrusion, 2) high temperature resin spread and infusion, 3) vacuum assisted resin transfer molding (VARTM), and 4) compression molding. The advantages and disadvantages of each process are discussed with emphasis on the high temperature resin infusion process. Composite laminates are characterized in terms of strength and stiffness under tension, bending, and shear in relation to longitudinal and transverse fiber orientations. Thermo-mechanical properties of the FRP composite sandwich panels including joint responses are presented in terms of: 1) the above different processes, 2) carbon fiber versus E-glass fiber, 3) vinyl ester resin versus epoxy resin, and 4) joint design and efficiency. The sandwich panels are evaluated at component and full scales under static four point bending loads and further analyzed using classical finite element models for their mechanical responses.