Concrete Bearing Research Articles

Concrete touchdown: new technology influences industrial buildings in Norway, 1912–1920

Construction technology developed quickly during the first decades of the twentieth century. This influenced the construction of industrial buildings at the UN Educational, Scientific and Cultural Organization World Heritage site of Rjukan and Notodden in Norway. Behind the construction was Hydro, a company founded in 1905 to produce synthetic nitrogen fertiliser to increase the world’s food production. This industrial development demanded large structures such as hydropower stations and production facilities. Concrete was introduced for the first time during this period, and systems are characterised by heavy concrete bearing walls and mixed bearing walls where concrete and steel were combined. Such systems demanded significant material resources and resulted in the development of steel and concrete skeleton frames. The development of viable systems was achieved through research in materials science and structural engineering, in both the USA and Europe. This paper discusses how concrete influenced construction and building systems at this site. Similarities to industrial buildings and other building typologies are evident and connect the site to the international context of architecture and engineering history. Understanding the characteristics of individual buildings and presenting them in an order of a construction systems will support the work of architects and engineers in future conservation schemes.

Research on the Construction of Zhuzhou Public Library under the Perspective of Cultural and Tourism Integration

In the construction of public cultural system under the background of the integration of culture and tourism, public library is an indispensable key element, which plays the important function of preserving human cultural heritage and providing cultural leisure. At the same time, the public library belongs to the social tourism resources, which is the indispensable cultural landscape in the modern society, and the concrete bearing and embodiment of the cultural spirit of a country or a city. Therefore, to strengthen the construction of public libraries and realize the integration of culture and tourism is not only to respond to the needs of national development, but also an important measure to improve the public cultural service system. This article proposes strategies for the construction of cultural tourism IP in public libraries and future strategies for the construction of smart public libraries through a survey of the current situation of characteristic cultural tourism resources and public library construction in Zhuzhou region. It has important practical and theoretical research significance for promoting the organic integration of tourism resource development and characteristic tourism in Zhuzhou.

Numerical Modelling of Bearing Strength of Concrete Strengthening with Carbon Fibre Reinforced Polymers (CFRP) Wrapping for Different Thickness of CFRP Sheet

The bearing strength of concrete plays an important role in transmitting the bearing force into the structural supports, especially for buildings and infrastructure such as concrete footings, concrete bridges, column corbels and concrete connections. The structural behaviour of the concrete bearing is related to the confinement effect, in which the load is transmitted to the concrete surface through the contact interaction between the steel bearing plate. However, extreme penetration on the contact surface of the concrete blocks by the steel bearing plate leads to failure modes on the concrete block. This research study focuses on the performance of the bearing strength of the concrete when it is wrapped with carbon fiber-reinforced polymers (CFRP) as the strengthening method. This research also examines the bearing strength of concrete when it is wrapped with a single layer of different thicknesses of CFRP sheet, which range from 1mm to 4mm thick. In order to understand the concrete bearing performance, a finite element model (FEM) using ABAQUS/CAE software is developed. An optimum meshing with a size 12.5mm is used for the further nonlinear analysis of the concrete model to discuss the results, such as the model validation by comparing the bearing strength results from the FE model with the Australian Standard, the comparison of the load-displacement curve for different thicknesses of CFRP wrapping, as well as the structural response or visualization of the concrete model. From the results, it shows that the different thicknesses of the CFRP wrapping significantly have a positive impact on the bearing capacity of the concrete, where the bearing strength of the concrete increases up to 26.16% as the thickness of the CFRP wrapping increases to 4mm for the optimum meshing size of 12.5mm. The FE visualization also shows various structural responses of the concrete bearing in the context of the deformation shape, vertical displacement, vertical stress distribution and max and minimum principal stress distribution of the concrete bearing, which are further discussed in this report

Research on mechanical properties of concrete by nano-TiC-BF-fly ash.

Ultra-high-rise buildings require high concrete bearing capacity. Ordinary concrete often fails to meet the project requirements. Admixture of admixtures in concrete is a means of solution. Currently, studies on the incorporation of basalt fiber (BF) and fly ash (FA) in concrete are relatively mature. However, research on incorporating nano-Titanium Carbide (nano-TiC) in concrete is still relatively scarce, which has a lot of room for development. To further improve the mechanical properties of concrete, BF, and FA synergized with nano-TiC were incorporated into concrete to produce TBF concrete in this study. And Response Surface Methodology (RSM) was used to optimize the mechanical properties of concrete. The collapse and compressive deformation damage characteristics of concrete were analyzed. The microstructure of the cement matrix was analyzed by the SEM (Scanning Electron Microscope). An optimization model of the TBF concrete craving function was developed. Optimized ratios with compressive, split tensile, and flexural strengths as response objectives were obtained, and the accuracy of the optimized ratios was investigated using the same experimental conditions. The results of the study showed that FA increased the collapse of concrete, while nano-TiC and BF decreased the collapse of concrete. Under uniaxial compression, nano-TiC, FA, and BF together incorporated into concrete can improve its compressive damage state. Moderate amounts of nano-TiC, BF, and FA could improve the mechanical properties of concrete. Their optimal mixing ratio admixtures were 0.88%, 0.24%, and 5.49%, respectively. And the measured values under the same conditions were compared with the predicted values. The maximum difference in compressive strength was 6.09%. The maximum difference in split tensile strength was 7.14%. The maximum difference in flexural strength was 8.45%. This indicated that the accuracy of the RSM optimization model was good. A moderate amount of nano-TiC, FA, and BF could improve the densification of concrete.

Numerical study on the design performance of wedge-type precast horizontal wall-slab joint for vertical load transfer

Construction of the residential buildings using large panel system (LPS) technology is an efficient and cost-effective way to provide housing to the populations at large scale. The main weakness of the system is the vertical load transfer at the joints. Horizontal wedge-type joints have known to perform well in load transfer from slab and the upper wall to the lower wall. However, limited research has focused on understanding the damage mechanism in the horizontal joints. This study is aimed at developing a finite element (FE) model of a horizontal wedge-type connection based on the experimental results. Parameters that affect the failure mechanism are transverse wall reinforcement, relative concrete strengths and slab bearing. These parameters were incorporated in the calibrated model to examine their effect on joint strength and damage progression. The results showed that the addition of transverse reinforcement improves the joint capacity and relative concrete strengths between joint and precast members influence the failure type. Furthermore, the comparison of simulation results with the existing design procedures showed that the design formulation, which is primarily focused on closed-type horizontal joints, shows good agreement with the simulation results and can therefore be used for the design of wedge-type joints.

МЕТОДИКА ОПРЕДЕЛЕНИЯ НЕСУЩЕЙ СПОСОБНОСТИ КОРРОЗИОННО- ПОВРЕЖДЕННЫХ КОЛОНН ПРИ СЕЙСМИЧЕСКИХ ВОЗДЕЙСТВИЯХ

During building and construction maintenance, corrosion of reinforced concrete bearing structures may occur due to various factors (errors at the design stage, exposure to external aggressive media, insufficient construction control, etc.). Thus, there is a need to develop certain methods of calculation of structures which take into account the effect of damage on load-bearing capacity and stability. To date, there are engineering methods for calculating corrosion-damaged reinforced concrete elements under the action of static and dynamic loads. However, there is a need to assess the bearing capacity of corrosion-damaged structures under seismic effects, both in verification calculations of existing buildings and at the design stage of buildings subject to corrosion of reinforcement due to increased aggressiveness of the environment or other negatively influencing factors. The paper discusses the developed methodology and test program for evaluating the seismic resistance of reinforced concrete columns at various levels of reinforcement damage. This test methodology is developed with the recommendations of GOST 27751. To ensure the reliability and mechanical safety of buildings and constructions, it is necessary to perform calculations using data from experimental studies of real building structures or models of construction sites and connection nodes.

Experimental Monitoring of Transition Zones in Railway Tunnels

Abstract The expert research activity of transition zones of tunnels is one part of the overall set of these places on the railway line. Typical places where the stiffness of the railway changes are the portals of tunnels, where undesirable deformations occur during the operation of trainsets due to the changes in materials. In the places of the portals, there can be a ballastless track or slab track (with concrete bearing layer) or classic structure with a railway ballast. The paper presents long-term research on monitoring height changes in these sections. The results of the expert activity will be the basis for the subsequent proposal of new measures, i.e. changes to built-in objects or modification of the materials of structural layers in a given place of the transition zone.

Tunnel lining segments with enhanced bearing capacity using hybrid concrete concepts

In general, the design of tunnel lining segments used in mechanized tunneling is dominated by the joints. In fact, the effects of partial area loading dominate segmental failure and, consequently, the concrete bearing capacity of the central region remains underutilized. This paper presents two types of new hybrid segments with enhanced utilization ratios throughout their bodies. The first type comes with strengthened longitudinal joints using high performance steel fiber reinforced concrete, in addition to conventional reinforcement. The second incorporates one-sided barrel-shaped recesses in the central region, which yield volume savings of up to 23.8%. The performance of the new designs is experimentally evaluated on a full-size testing rig made from two steel frames with a capacity of 5MN each. It captures the on-site conditions in tunnels during service (final state). The first type of segments shows a 74.3% higher loading capacity than a conventional specimen for reference. The second performs even better and possesses 97% higher capacity. In both cases, the failure occurs in the central region. This increases structural safety and simplifies the design. Especially the design of the central region subjected to bending and axial forces gains more relevance against the controversially discussed design of the longitudinal joints.

Experimental investigation on shear behavior of bamboo-concrete composite structure with perforated steel plate connection

In order to fully utilize the high tensile strength of bamboo while mitigating the drawbacks of its small elastic modulus and large deformation, a composite structure combining bamboo and concrete was employed. The transfer of longitudinal shear force between the two materials was accomplished by capitalizing on their respective advantages and minimizing the relative slip at the interface. This study proposed a bamboo-concrete composite (BCC) structure utilizing a perforated steel plate (PSP) as a shear connection. An experimental investigation was conducted, exploring different combinations of several parameters, including the aperture size of the PSP, the concrete strength, the presence of penetrating steel bars, and the diameter of the penetrating steel bar. Sixteen groups of BCC structure with PSP connection were tested, and the failure mode, ultimate bearing capacity, and relative interface slip of the structures were analyzed. The test results indicate that as the concrete strength increases, the stiffness and bearing capacity of the connection also increase. However, the corresponding slip at the ultimate load diminishes. Under the condition where the concrete strength and the diameter of the penetrating steel bar are the same, the larger the aperture size of the PSP, the lower the stiffness of the connection, and the greater the slip corresponding to the ultimate load. Furthermore, a larger diameter of the steel bar results in greater connection stiffness and decreased slip at the ultimate load. Drawing on the shear capacity calculation formulas proposed by scholars for PSP connections, this study integrates the experimental results into these formulas and compares them with the actual outcomes. Through a comprehensive assessment of the primary factors influencing load-bearing capacity, a shear capacity calculation formula specifically designed for the BCC structure with PSP connections is proposed and developed.

Experimental and Numerical Study of Concrete Fracture Behavior with Multiple Cracks Based on the Meso-Model.

In this paper, a series of experimental and numerical studies were carried out to investigate the effect of multiple cracks on concrete fracture behavior. Seven groups of double-crack concrete three-point bending (TPB) experiments with different crack lengths and different crack distances were carried out. The experimental results showed that the bearing capacity of double-crack specimens was slightly larger than the standard specimen with one central crack. Additionally, with an increase in the second crack length or with a crack distance reduction, the concrete's bearing capacity increased correspondingly. Based on the experiments, a numerical meso-model was developed based on applying cohesive elements. The aggregate, mortar, interface transition zone (ITZ), and potential fracture surfaces were explicitly considered in the model. In particular, cohesive elements were used to characterize the mechanical behavior of the ITZ and potential fracture surfaces. A modified constitutive concrete model was developed by considering the potential fracture surfaces' damage relation and friction effect. The accuracy of the developed meso-model was validated through a comparison between simulation and experiments. Based on meso-models, the influence of multiple cracks on the concrete bearing capacity was investigated by analyzing the energy evolution. The analysis results showed that the bearing capacity has a linear relation with the proportion of mode II energy consumption during the fracture process, which explains why specimens with multiple cracks have a slightly larger bearing capacity than the standard specimens. In summary, this study has found that in three-point bending fracture tests primarily characterized by mode I fractures, the presence of multiple cracks near the main crack slightly enhances the load-bearing capacity of the specimens. This is attributed to a slight increase in internal energy dissipation associated with the presence of these multiple cracks.

General Prediction Models for Local Bearing Capacity of Concrete

The local bearing capacity is a basic mechanical property, which is crucial in the post-tensioned anchorage zone design. However, it is challenging to accurately predict local bearing capacity due to the disordered and complex stress conditions in anchorage zone. The existing prediction models have limited application scope, which are difficult to meet the application requirements of novel materials. In this study, the objective is to develop the general prediction models for evaluating concrete local bearing capacity. A reliable database was established based on the test result datasets collected from this study and previous studies. Then, the influence of concrete strength, local area aspect ratio and duct was analyzed. The calculation model was obtained based on fitting analysis (FA) and artificial neural network (ANN) technology. Besides, both the FA model and ANN model were proven to accurately predict concrete local bearing capacity, according to the prediction performance comparisons with existing typical prediction models.

Grey Correlation Analysis of the Durability of Steel Fiber-Reinforced Concrete under Environmental Action.

The interface performance of steel fiber-reinforced concrete (SFRC) is a critical factor in determining mechanical properties and durability. The degradation of the concrete matrix and micro-structure interface is caused by environmental erosion, which shortens the service life of the structure design. Considering different volume contents of steel fiber (0%, 1%, 2%), the failure mechanism of SFRC under different environmental erosion conditions was studied through a laboratory test scheme. A total of six environmental factors are selected, including water, sodium chloride solution, sodium sulfate solution, dilute sulfuric acid solution, sodium hydroxide solution, and a freeze-thaw cycle. When subjected to different erosion concentrations and periods, micro-structure and axial bearing capacity deterioration laws are compared and analyzed. A durability equation related to fiber mixture ratio and strength is presented based on the experimental data and the numerical simulation method. The influence of different environments on steel fiber-reinforced concrete is analyzed, and the grey correlation degree of axial compressive strength is analyzed. The experimental results show that steel fiber can effectively improve the concrete axial bearing capacity, but different responses are observed under the various erosion conditions. A freeze-thaw cycle environment has the most significant impact on the axial compressive strength of concrete, followed by the sulfuric acid environment, and other environments have a weaker impact. The research results will provide a theoretical basis for predicting the performance deterioration of SFRC concerning other erosion conditions and periods.

Experimental investigations of foamed concrete with recycled waste glass powder wall panels

AbstractMillions of tons of waste glass are produced globally. The use of waste glass in concrete is an environmentally friendly solution, contributing to sustainable construction practices. This study investigates the potential of using recycled waste glass powder (RWGP) in foamed concrete nonload bearing wall panels as acoustic barriers. This study investigates the axial and flexural behavior of wall panels constructed with foamed concrete incorporating RWGP. A total of ten 900 mm long and 700 mm wide wall panels of foamed concrete with RWGP reinforced with 7.6 mm diameter steel mesh were cast and tested. Five wall panels were 75 mm thick and reinforced with one layer of steel mesh and the other five wall panels were 120 mm thick and reinforced with two layers of steel mesh. The experimental results exhibited that 120 mm thick wall panels sustained significantly higher peak axial and flexural loads, bending moments, axial deformations at peak axial load and midspan deflections at peak flexural load than 75 mm thick wall panels. The available design codes of masonry structures underestimated the peak axial loads and the bending moments of wall panels by about 9% and 17%, respectively.

Modifikasi Mesin Pengupas Pinang Belah Kering Model Thresher

Modify the palm fruit thresher machine into a thresher model dry split betel nut peeler by testing the tool so that it can find out the constraints of the palm fruit thresher machine, and disassembling the components or parts to be modified, namely; cover, collection channel, blade and drive clutch. The cover is designed to function to be sturdy from the impact of areca nuts and is cylindrical. The reservoir channel is designed to allow the peeled betel nut to enter the drain pipe and the blower is in charge of blowing between the peeled betel nut and the seeds. The blade is designed to peel the dry split betel nut. The drive clutch is designed to function as a connector/breaker for the engine rotation to the shaft and plain concrete iron and bearings as a v-belt retainer. In the test with a capacity of 50 kg 1 day drying, peeled 40 kg and unpeeled 10 kg with an average time of 15 minutes is the best test. Therefore, we can conclude that the best peeling results from this dry split betel nut peeler machine are almost 80% peeled.

A Case Study on Condition Assessment of Fire-Damaged RC Members of Turbo-Generator

Many researchers across the globe have carried out fire safety risk analysis to gather evidence and pertinent data for different Reinforced Cement Concrete (RCC) members exposed to fire. Assessment of fire-damaged structures furnishes the minute details of the effect of fire on the properties of concrete.The study indicates the condition assessment of the turbo-generator (TG) unit, comprises of concrete bearing pedestals, deck and supporting columns. The research was conducted using Non-Destructive Testing (NDT) techniques using Rebound hammer test, Ultrasonic Pulse Velocity (UPV) test, Concrete Cover measurement, Carbonation and Crack depth measurements followed by microstructural studies using an X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), Optical Microscope (OM), and Mercury Intrusion Porosimetry (MIP). The samples were taken from a fire-damaged concrete bearing pedestal B2 and a non-fire-damaged concrete bearing pedestal B4 of the TG unit. The approach enabled us to find the extent of damage to the RCC members exposed to fire. The above mentioned test witnessed that the concrete bearing pedestal B2 was the moderately distressed member, expressed doubtful quality of concrete, higher porosity, reduced residual compressive strength and reduction in yield strength of steel. However minor distress in form of crushing at the top grout portion was observed in concrete bearing pedestal B4, and no apparent distress was observed in supporting columns of TG unit. Based on the distress identified, repair and remedial measures were proposed to concrete bearing pedestals in order to improve the performance of the TG unit.

Behavior of railroad bearing due to temperature and load using LISA FEA

A very important element of railway is the rail bearing, different types of rail bearings that we know in Indonesia are wooden rail bearings, concrete rail bearings. In this study, the stress behavior that occurs in the two types of railway bearings due to the load and the occurring temperature effect is to be checked.
 It was found that the stress occurring in bearings with different materials, namely concrete and wood, when the The nominal stress can be seen on the concrete bearing is 11.87 N/mm2, on the wooden material the bearing load is 10.41 N/mm2. As for the temperature effect, it looks similar to the temperature of 80 °C for each material, but it can be seen that the temperature effect spreads from the surface due to the friction between the railroad tracks and the railroad wheels.

Effect of Wire-Mesh Type on Strengthening Reinforced Concrete Beams

Structural strengthening is a method of application to raise the load-ability capacity of building structures to meet the building's need to carry additional and unexpected loads that were not accounted for in the main design. In this study, Ferro-cement was used for strengthening concrete beams. Three locally available wire mesh types were used with an ordinary cement mortar to strengthen reinforced concrete beams under flexural loading. The results show that using a Ferro-cement layer with wire mesh of 15 mm size square opening has the best effect on increasing reinforced concrete beams' bearing capacity and deflection more than when using the other two types of meshes. The first crack and failure load increases were 72 and 79%, respectively. In contrast, the deflection increased 70 and 51% at the first crack and failure load.

Effect of different fibers on impermeability of steam cured recycled concrete

Recycled concrete solves the problems of building resource waste and environmental pollution. The addition of fiber can improve recycled concrete's bearing capacity and durability. In order to study the influence of different fibers on the impermeability of recycled concrete, macro and micro experiments were carried out on 60 compressive samples and 30 impermeability samples with a different fiber content of 0%, 0.5%, 1.0%, and 1.5% in this paper. The effects of steel fiber, polypropylene fiber, and glass fiber on the impermeability of recycled concrete were explored. The compressive strength, impermeability height, and economic cost of the sample were evaluated through multi-criteria optimization, and the optical fiber type and content were obtained. The results show that the addition of fiber can improve the overall compactness of the internal structure of recycled concrete, inhibit the expansion and extension of micro-cracks in the sample, and improve the compressive strength and impermeability of recycled concrete. Among them, the compressive strength and impermeability can be increased by 15.36% and 34.41%. However, when the content of the three fibers exceeds 1.5%, the increased range shows a downward trend, indicating that 1.0% steel fiber and 1.0% glass fiber have the best improvement effect on the compressive strength and impermeability of recycled concrete. Finally, the multi-criteria optimization results show that the selection of 1.0% polypropylene fiber and glass fiber is the best fiber type and content to improve the compressive strength and impermeability of the sample.

Effect of Thermal Bridges of Different External Wall Types on the Thermal Performance of Residential Building Envelope in a Hot Climate

In this paper, the thermal performance of residential building envelopes including thermal bridges (TBs) in a hot climate, using four different exterior wall types, is modelled and assessed. TBs at the junctions between columns and walls and between walls and slabs of the ground floor, roof, and intermediate floors are considered. The tested wall types are classical (two layers of cement blocks with insulation in between), autoclaved aerated concrete bearing (AAC-B), AAC column and beam (AAC-CB), and exterior insulation and finish system (EIFS). The results indicated that thermal bridges have a considerable effect and determine the best external wall type which was the EIFS that has a continuous exterior insulation. EIFS proved to reduce the heat transmission with the outdoor environment for residential buildings by 101.8, 51.2, and 13.9% than the AAC-CB, AAC-B, and classical walls, respectively. Thermal bridges effect on the building envelope using the EIFS is insignificant as the thermal resistance of the envelope and wall differs by less than 1% for small areas. The overall heat transfer coefficients for small buildings are larger than those for large buildings by 8–26%. As the number of intermediate floors increases from 1 to 50, the envelope overall heat transfer coefficient increases by 4.5% for the EIFS, 14.1% for classical, and 19.5% for AAC-CB walls. The AAC-CB, as the common practice wall structure in many hot climate countries, has the lowest performance among the tested wall types.

Experimental study on corrugated steel–concrete composite semicircular arches under midspan loading

Corrugated steel–concrete composite arch is a novel structural form that increases the load-bearing capacity of corrugated steel (CS). In this study, the static performance of a CS-plain concrete (CSPC) semicircular arch and CS-reinforced concrete (CSRC) semicircular arch was experimentally investigated under midspan loading using six arch specimens. The performance of four CSPC arch specimens with different bond strengths and concrete strengths was tested and compared. The results showed that insufficient bond strength between CS and concrete caused concrete breakout failure and affected the ultimate bearing capacity significantly, with the largest reduction of 62%. Therefore, adopting a high concrete strength can significantly improve the concrete cracking load and bearing capacity of CSPC arches. Subsequently, a CSRC arch was also tested, together with a reinforced concrete (RC) arch, to investigate the failure mode and ultimate bearing capacity. It was found that because of the high moment of inertia and contribution of the CS to the shear strength, the stiffness and ultimate bearing capacity of the CSRC arch were higher by 86% and 90%, respectively, than that of the RC arch with the same amount of concrete and steel. In addition, based on the measured strain, composite and confining effects were observed in the CSRC arch; however, the confining effect was negligible.