Non-structural Members Research Articles

Investigating the Viability of Rubber Crumbs from Waste Tyres as Partial Replacement for Coarse Aggregates in Concrete

The number of waste tyres is on the increase, because of the growing use of transport vehicles. Almost one trillion waste tyres are generated in the world annually. Established methods of disposal, recycling and re-use of waste tyres have failed to keep pace with generation, proven to be ineffective, cost-intensive and in some cases environmentally unsustainable. This study aims to investigate the effects of utilizing crumbs from discarded rubber as a partial replacement for coarse aggregates in concrete. Rubber crumbs of 10 – 20mm nominal size were produced manually from waste tyres. The rubber crumbs were used to replace 10%, 20% and 30% of coarse aggregates in design concrete of 20N/mm2 target compressive strength. The effects of this material on the slump, water absorption and compressive strength of concrete were examined. The inclusion of rubber crumbs resulted in a decline in the slump of concrete up to 10% relative to the control specimen. Water absorption increased marginally at 10% replacement compared to the control specimen and recorded a maximum value of 0.77% with 30% replacement after 28 days of curing. The compressive strength of the concrete was negatively affected by the rubber crumbs. The maximum value of 13.9N/mm2 was attained at 10% replacement after 28 days of curing. Rubberized concrete with 10% replacement of coarse aggregates can be used for non-structural concrete members such as roof slabs, non–load–bearing partition walls, and roadside barriers. Chemical treatment of rubber crumbs to improve surface adhesion properties should be encouraged.

A review on serviceability of foam concrete

In the face of the present global warming crisis, building energy conservation and emissions reduction have gained increasing attention. In the sustainable development of buildings, foam concrete has become increasingly popular in the construction industry due to its excellent thermal insulation, sound insulation and fire resistance. Foam concrete employed in buildingand construction (used as either a structural or non-structural member) must meet certain serviceability criteria. This paper reviews the serviceability of ordinary Portland cement (OPC) foam concrete, geopolymer foam concrete (GFC), sulphoaluminate cement (SAC) foam concrete, magnesium phosphate cement (MPC) foam concrete and limestone calcined clay cement (LC3) foam concrete, to include drying shrinkage, creep, thermal conductivity, water absorption and acoustic properties. Subsequently, it is proposed to change the initial curing conditions to reduce drying shrinkage, add glass fiber and basalt fiber to improve creep performance, increase heat flow direction resistance and extend the thermal conduction path to reduce thermal conductivity, control slump flow to regulate water absorption, and combine sound absorbing foam concrete with sound reflecting materials to achieve a comfortable and low noise living environment. Finally, ideas and suggestions for future work are proposed.

<b>Method for Estimating Bending Stiffness of Concrete Girders during Train Passage Considering Effects of Concrete Cracks and Non-structural Members</b>

<b>Method for Estimating Bending Stiffness of Concrete Girders during Train Passage Considering Effects of Concrete Cracks and Non-structural Members</b>

Rotational Stiffening Performance of Roof Folded Plates in Torsion Tests and the Stiffening Effect of Roof Folded Plates on the Lateral Buckling of H Beams in Steel Structures

Non-structural members, such as roofs and ceilings, become affixed to main beams that are known as structural members. When such main beams experience bending or compressive forces that lead to lateral buckling, non-structural members may act to restrain the resulting lateral buckling deformation. Nevertheless, neither Japanese nor European guidelines advocate for the utilization of non-structural members as lateral buckling stiffeners for beams. Additionally, local buckling ensues near the bolt apertures in the beam–roof folded plate connection due to the torsional deformation induced by the lateral buckling of the H beam, thereby reducing the rotational stiffness of the roof folded plate to a percentage of its ideal stiffness. This paper conducts torsional experiments on roof folded plates, and with various connection methods between these plates and the beams, to comprehend the deformation mechanism of roof folded plates and the relationship between their rotational stiffness and the torsional moment. Then, the relationship between the demand values against restraining the lateral buckling of the main beam and the experimentally determined bearing capacity of the roof folded plate is elucidated. Results indicate the efficacy of utilizing the roof folded plate as a continuous brace. The lateral buckling design capacity of H beams that are continuously stiffened by roof folded plates is elucidated via application of a connection method that ensures joint stiffness between the roof folded plate and the beam while using Japanese and European design codes.

Adaptive and Sustainable Design for Building Construction Considering Climate Change

The two most crucial factors that are constantly taken into account while developing or building any new infrastructure in this day and age are sustainability and resilience. In a similar manner, this project centers on the same idea of sustainability and resiliency in order to construct a 10-story structure that served the function of a multipurpose community center equipped with cutting edge technology and carefully selected construction materials in order to lessen the number of harmful emissions and to keep a balance in both the structural strength and the environment. The design process has involved choosing the primary building material, the type of construction used, the building plans, and the carbon footprints the selected building materials are generated. The building’s planned design also assessed for structural soundness, environmental sustainability, and resilience. The outcomes are compared to an existing structure in the same domain for the critical evaluation and effective decision-making. As a result, this compilation also includes a complete and in-depth analysis of how the suggested construction is more robust and sustainable. The preface also includes information on the building parts, such as the materials used to contrive the structural as well as the non-structural members. In the end, the suggested design is monitored based on its structural qualities to ensure its stability and resilience. In order to successfully propose a sustainable and resilient design for the building of a multipurpose 10-story community center, a comprehensive and optimal set of recommendations is provided.

On the coupled dynamics of vertical cladding panels and industrial frame structures subject to out-of-plane seismic loading

Industrial facilities typically consist in large-span single-storey prefabricated buildings having a rectangular floor space. Frame structures made with either steel, timber or precast concrete members are mostly employed to support the roof, while cladding panels create the building enclosure. Their interaction with the frame typically plays a relevant role in the overall building dynamics, potentially leading under seismic excitation to both local and global collapses. Experience shows that a critical component failure is that of the panel-frame connection. Current design approaches classify the panels as “non-structural members” and the forces at the connections induced by the out-of-plane seismic loading are evaluated with approximate expressions. Neglecting the dynamic interaction between the panel and the frame, however, may lead to an oversimplified description of the mechanical problem and inaccurate estimates of the forces at the connections. To overcome these drawbacks, in this work a different approach is pursued in which the interaction between the fundamental sway mode of the frame and the out-of-plane motion of the cladding panel is studied within a rigorous mechanical setting. The focus is on the very frequent case of vertical cladding panels, supported at the ground and retained out-of-plane by the frame. Starting from the development of the equations of motion for the coupled frame-panel structure, a minimal set of parameters controlling the dynamics of the system is identified. The spectral properties of the structure are analytically investigated to gain a clear insight on the coupled frame-panel structure. This is characterized by frequency veering and hybridization between the mode deforming the frame and the local modes of the panel. The system response for seismic excitation, then, is studied with a stochastic approach. Parametric analyses focusing on the values of the forces at the top and bottom connections of the panel and on the lateral displacement of the frame show that while the frame drift is controlled mainly by the first mode of the coupled frame-panel system, the top and bottom connection forces of the panel require at least consideration of the first two modes of the coupled system. This information is of great importance in deriving a reduced model of the coupled system. The proposed procedure allows for a thorough understanding of the coupled system dynamic response, and represents a viable alternative to derive the design response quantities of interest.

Effectiveness of structural walls in improving the serviceability of a seismically-retrofitted RC building

AbstractA moderate earthquake with a magnitude Mw of 6.8 hit the Elazig Province of Turkey on January 24th, 2020, causing fatalities and structural damage/failure. Following the earthquake, a field reconnaissance was conducted at the Administration and Operation Campus of Karakaya Dam, which is 19 km from the earthquake epicenter. The exhibited performances in two side-by-side nominally identical reinforced concrete (RC) buildings with the same material properties and soil conditions differed significantly. The main reason lies in the preventive action taken before the earthquake in one of the buildings. The building retrofitted with additional structural walls had a slight/no damage level. However, the non-retrofitted building suffered severe damage due to large cracks in numerous infill walls, some of which were exposed to partial collapse. That makes the non-retrofitted building unserviceable, requiring evacuation after the earthquake. The field-observed building damage was compared with the seismic performances acquired from their refined numerical models for the recorded ground motions. The photographic documentation exposing the entire performance and damage level in non-retrofitted and retrofitted buildings was quantified by static pushover and nonlinear response history analyses. The post-earthquake performance of nonstructural members in retrofitted and non-retrofitted buildings was simulated with reasonable accuracy.

Development of a high-performance blast energy-absorbing system for building structures

Shock absorbers have been widely used in the automotive and aeronautical industries for many years. Inspired on these devices, the paper presents an analytical and numerical assessment of a high performance protective system for building structures against blast loads, which is composed of a shielding element connected to the main structure, at the floor levels, through ductile Energy Absorbing Connectors (EACs). The EACs exploit the external tube inversion mechanism to absorb a significant part of the imparted kinetic energy from the blast wave. While the system prototype has been developed in laboratory, it was characterized and tested in a full-scale blast testing campaign. A validated finite element model was used next to analyze its performance in a more demanding design scenario. The introduction of EACs notably reduces the peak horizontal loads and the kinetic energy transferred to the protected structure, being expected a significant reduction of the stresses in the supporting vertical elements, in addition to the protection of structural and non-structural members. These results encourage further studies of the presented protective system that can be potentially employed for a large variety of blast threat scenarios, especially when increasing the stand-off is not a possible/viable option and sensitive facilities have to be protected.

塩化ビニル管の繰返し曲げ挙動

Many buildings have been reported to stop their service due to damage to non-structural members such as equipment piping after large-scale earthquakes. Although data on deformation capacity and strength of carbon steel pipe for ordinary piping is being collected, few studies are conducted on polyvinyl chloride pipes (PVC pipes) for drainage. Cyclic bending tests are conducted of PVC pipes with nominal diameters of 40A, 50A and 75A to evaluate their deformation capacity and strength. The result is that the deformation of PVC pipes is larger than that of steel pipes, and shows brittle failure.

Analysis of Seismic Collapse-Resistant Influencing Factors of RC Frame Structure

The RC frame structure is widely applied in China due to its flexible layout and good anti-collapse capacity during an earthquake. However, a lot of RC frame structures collapsed in the strong earthquake zone during the Wenchuan earthquake. The collapse resistance of the RC frame structures during an actual earthquake is inconsistent to the designed seismic collapse resistance in a project. So the collapse resistance of reinforced concrete (RC) frame structures during an earthquake and its influencing factors are a hot research topic in the field of earthquake engineering. Based on the research results of scholars in recent years, this paper briefly discusses the evaluation criteria of structural collapse, the structural collapse mechanism during a real earthquake and the influence of nonstructural components. Finally, the influencing factors are summarized in terms of design methods, plastic hinges and nonstructural members, which have certain reference significance for the seismic collapse resistance design.

Earthquake-induced loss assessment of steel dual concentrically braced structures subjected to near-field ground motions

Steel structures with dual systems, including special moment-resisting frames (SMRFs) and special concentrically braced frames (SCBFs), have found extensive applications in seismically active regions due to their considerable lateral stiffness and ductility. However, the seismic performance of such system has not been investigated subjected to near-field ground motion records. To address this research gap, this paper evaluates collapse risk and earthquake-induced loss of multi-story steel structures with dual concentrically braced frames. A comprehensive seismic performance assessment is conducted on selected five-, 10-, and 15-story structures subjected to near-field ground motions (NF-GMs) with and without pulses based on the methodology provided in FEMA P-58. The results are also used to assess the effect of NF-GMs with pulses on the seismic performance measures, such as life-cycle cost and repair time of the studied structures at different seismic intensity levels. Finally, the contribution rate of collapse and demolition of structures, and contribution of structural and nonstructural members in the repair cost and time of the steel structures are estimated and compared subjected to NF-GMs. It is concluded that collapse and demolition loss play significant roles for NF-GMs with and without pulses, respectively, while the seismic collapse behavior is governed by the ratio of the pulse period of the GM to the period of the first mode of the structure.

Prediction of axial load capacity of cold formed lipped channel section using machine learning

Cold Formed steel channel sections are widely used as both structural and non-structural members. The axial load carrying capacity of Cold Formed steel sections depends on buckling modes such as local, distortional, global buckling, their interactions and geometrical imperfections. Although existing standards are adequate for determining axial load-carrying capacity, the present study proposes an alternative method based on recent machine learning algorithms. Experimental data pertaining to axial load tests conducted on Cold Formed steel lipped channel sections are collected and modelled using the finite element method. Validated finite element models are used further to generate the input–output data set by sampling the input geometric and strength parameters of the section required for training machine learning models. Latest machine learning models, namely Linear Regression, Lasso Regression, K-Nearest Neighbours, Decision Tree, Random Forest, Adaptive Boost, Extreme Gradient Boosting, Light Gradient Boosting Machine, Categorical Boosting, Gradient Boosting Regression, Support Vector Machine and Artificial Neural Network, are used in this study to predict the axial load capacity. The Random Forest model is the best-performing algorithm for axial capacity prediction, with an accuracy of 99.10% for the test data set. Further, SHapely Additive exPlanations analysis is carried out to estimate the order of significance of the input variables and to justify the prediction of the best-performing machine learning model.

Evaluation of collapse resistance of masonry-infilled RC frame building under blast loadings

As non-structural members, the masonry-infilled (MI) walls are always ignored in the numerical and experimental study on the blast and collapse resistance of RC frame buildings, while the contribution of MI walls on preventing the large-scale collapse has been observed according to the past explosion incidents. This paper aims to propose and verify a numerical simulation approach considering the blast- and collapse-resistant effects of MI walls, and further evaluate the collapse resistance of MI RC frame buildings under blast loadings. Firstly, based on our previously validated hybrid finite element (FE) modelling approach for RC frame structures and Multi-material Arbitrary Lagrangian-Eulerian method for applying blast loadings, the simplified micro-model and compressive strut model of the MI wall were adopted to characterize its blast and collapse resistance in the near- and far-regions of building, respectively. Secondly, the out-of-plane explosion test and in-plane quasi-static collapse test were numerically reproduced to verify the applicability of adopted FE modelling approaches for MI walls. Furthermore, by establishing the hybrid FE models of prototype bare and MI RC frame buildings, the propagation of blast waves, damage modes as well as dynamic responses of RC frame buildings under two design-based threat of explosion at corner and side columns were derived and examined. Finally, the applicability of the anti-collapse design method specified by U.S. Department of Defense, i.e., alternate path method (APM), for RC frame buildings under external explosions was examined. It derives that, (i) the presence of MI walls can efficiently block the blast waves into the building structures, and relieve the upward arch of slabs and damage degree of interior columns; (ii) compared with the bare RC frame buildings, the MI walls provide sufficient alternate load paths to enhance the structural robustness and restore the gravity stability of MI RC frame buildings after the explosions; (iii) the APM is only applicable to evaluate the collapse resistance of MI RC frames under the external explosion of cargo van bomb (1814 kg of equivalent TNT) or even less charge weight.

CYCLIC BENDING TESTS ON SEVERAL DIAMETERS CARBON STEEL PIPE FOR ORDINARY PIPING

Many buildings had stopped their service due to damage to non-structural members including ceilings, partition walls and piping after large-scale earthquakes. In particular, piping-failure-caused water leakage damaged electronic equipment and resulted in a loss of functionality of the building. Cyclic bending tests are conducted of carbon steel pipes for water supply piping with nominal diameters of 25A, 40A, 50A and 80A to evaluate their deformation capacity and strength. The results are summarized as follows.

Evaluation of Seismic Acceleration Demands on Mechanical Support Systems

Earthquakes are among the most influential force of nature that affect human life. Reconnaissance after the severe earthquakes pointed out that seismic performance of non-structural members and elements could be as significant as the structural members in lateral force-resisting systems. As such, it is important for design engineers to recognize the seismic demand on the mechanical systems that support the critical non-structural components (e.g., sprinklers, electrical and mechanical equipment, etc.) in terms of the safety during and after an earthquake as well as functionality and retrofitting cost after an earthquake. The primary goal of this study is to systematically investigate the seismic demands on the mechanical support systems of a typical mid-rise steel structure. For this purpose, non-linear time history analyses are carried out using a suite of ground motion acceleration records to evaluate the seismic demands on both seismic force-resisting system and the support system by means of inter-story drift angle and horizontal accelerations, respectively. Results obtained from the analyses are discussed considering the requirements stipulated in the current national and international buildings and recommendations are made.

A Comprehensive Review on Construction Applications and Life Cycle Sustainability of Natural Fiber Biocomposites

The construction industry is continuously searching for sustainable materials to combat the rapid depletion of global resources and ongoing ecological crises. Biocomposites have recently received global attention in various industries due to their renewability, low cost, and biodegradability. Biocomposites’ potential as a sustainable substitute in construction can be understood by identifying their diverse applications. Moreover, examining their life cycle environmental and economic impacts is important. Therefore, this study is a novel attempt to encompass biocomposites’ construction applications and their environmental life cycle performance. Statistical analysis is done related to the temporal distribution of papers, publishers, literature type and regions of studies. First, this paper reviews the latest research on the applications of natural fiber biocomposites in construction with their key findings. The applications include fiber reinforcements in concrete, external strengthening elements, internally filled hollow tubes, wood replacement boards, insulation, and non-structural members. The second part covers the life cycle assessment (LCA) and cost studies on biocomposites. The life cycle studies are currently rare and require more case-specific assessments; however, they highlight the benefits of biocomposites in cost savings and environmental protection. Finally, this study provides key suggestions for increasing the applicability of biocomposites as sustainable construction materials.

Seismic resilience assessment of self-centering prestressed concrete frame with different energy dissipation ratio and second stiffness

This paper presents the effects of two key parameters, energy dissipation ratio and second stiffness, on the seismic performance and resilience of self-centering prestressed concrete (SCPC) frames. The dynamic parametrical analyses under different earthquake intensities and fragility analyses under different performance level have been carried out, the maximum drift (MD) - residual drift (RD) joint probability density method suitable for SCPC structure was proposed, and the damage distribution law of structural members and typical non-structural members was analyzed. The influence of different parameters on the resilience indicators of SCPC framework was studied based on the FEMA P-58 resilience assessment framework. The results indicate that the main structure of the SCPC frame remained intact, while the acceleration-sensitive non-structural components accounted for more than 80% of the total repair cost and repair time. Increasing the second stiffness could reduce the high-order modal effect of the SCPC structure response and the loss in the upper part of the SCPC frame. Increasing energy dissipation ratio could reduce the maximum response of the structure and improve the building resilience. When the energy dissipation ratio was increased from 0.2 to 0.8, the repair cost and repair time were decreased by 13.1% and 17.2%, respectively, under maximum considered earthquake (MCE), and the residual displacement of the structure was still within the re-centering limit of 0.2%.

Mechanical and durability performance of lightweight concrete (LWC) from colombian thermally expanded clay aggregates

Lightweight concrete (LWC) has become an outstanding material in the construction sector to conform non-structural and structural members into buildings. Expanded clay aggregate is a special type of lightweight aggregate formed by heating clay with little lime content, having low unit weight, high durability, and mechanical strength. Despite the massive use of the expanded clay lightweight aggregate worldwide, their use in the Colombian context is still limited. This research reports the characterization of the behavior of lightweight concrete from Colombian expanded clay aggregates. Experimental tests on fresh and hardened state (compressive strength, apparent density, and chloride migration) were carried out on lightweight concrete added Colombian expanded clay aggregate. It was found that the inclusion of up to 50% of the Colombian expanded clay aggregate causes a 15% workability decrease, 36% compressive strength decrease, 22% apparent density decrease as well as 34% decrease in the chloride migration coefficient of the lightweight concrete. In the same way, the lightweight concrete added with 50% of Colombian expanded clay aggregate meets the lightweight concrete requirements prescribed by the ACI 318 building code in terms of compressive strength, and unit weight. From the results, it is concluded that the use of Colombian expanded clay aggregate added up to 50% by weight of conventional aggregate is feasible to manufacture structural lightweight concrete.

Shake table tests on a full-scale six-storey cold-formed thin-walled steel-steel plate shear wall structure

To evaluate the seismic response of a multi-storey cold-formed thin-walled steel (CFS) structure based on the influence of nonstructural members, shake table tests were conducted on a full-scale six-storey CFS-steel plate shear wall structure (SPSWS) using bidirectional seismic inputs. The building specimen was tested at two different stages. In the first stage, the specimen mainly included structural components of walls, floors, and roofs, whereas the second stage model included all the nonstructural components. The testing program and obtained results including the observed damage, dynamic characteristics, strain response, acceleration, and displacement response were presented. Overall, this study revealed that the skin effect of lightweight wall panels, together with steel plate shear walls, resisted horizontal earthquakes and demonstrated the excellent deformation capacity and seismic performance of the CFS-SPSWS building.

Comparative Study on Damage Index of RCC Frame Considering Fiber Discretization Technique

Abstract: Damage indices which take into account both maximum deformation and cyclic effects were developed by Park and Ang. In the field of structural engineering, it’s observed that the Park and Ang damage index is mostly used for RCC structure. The damage index parameter assessed based on plastic hinge approach which is not effective to consider the coupled response between axial force and flexural moment especially in nonlinear domain. The accurate damage evaluations of structure are depending on other parameter such as, accurate modelling of frame, selection ground motion records. Masonry infill walls are widely used as partitions all over the world. Commonly masonry walls are not considered in the damage evaluation process because they are supposed to act as non-structural members or elements. Fiber discretization technique is used to consider inelastic behaviors of member. Single strut is model as infill wall in multidirectional. Results obtained from this study show that the accuracy of damage index totally depends on damage parameter consideration and modeling of building. The coupled effects give more realistic damage of structure as compared with other damage parameters.