Uji Eksperimental Sambungan Pelat Baja Perantara dengan Sekrup Kunci pada Hubungan Balok-Kolom Kayu Meranti Merah

In current design procedures, the capacities of single-shear timber connections with lag screws are determined based on their governing failure modes, which are assumed to occur independently. In this study, the capacity and failure modes of single-shear timber connections with lag screws are evaluated experimentally and numerically. Six specimens of Red Meranti wood and lag screws with different penetration lengths are tested to obtain their lateral load capacities and failure modes. Nonlinear 3D finite element analyses using Abaqus are conducted to simulate the test condition. The experimental and numerical results are evaluated in terms of connection failure modes and capacities. Moreover, the result will be compared with NDS 2018 predictions. The study results show that the connection capacities between experimental tests and numerical analysis are similar if the minimum penetration requirement of NDS 2018 is satisfied. It can also be seen that the dominant failure modes, both from experimental and numerical results, match with those predicted using NDS 2018, although they are slightly combined with the other failure modes.

Red Meranti is a high-quality commercial wood that can be used outdoors. Outdoor timber will be exposed to the weather so that, in the long period, it will cause discoloration. This study aims to determine the colour change of meranti wood due to weather exposure for five months. Observation of macroscopic and colorimeter changes in the colour of red meranti wood refers to the ASTM D2244 standard. The results showed that red meranti wood at the beginning of the study was brownish red with L* 64.67, a* 16.13, and b* 17.00. After 150 days, it turned greyish black with L* 50.74, a* 1.25, b* 3.41, and ΔE 24.50. Colour changes in L*, a*, and b* parameters for 150 days followed the estimated growth curve pattern.

This research aims at investigating the effectiveness of fire retardant siliceous based materials which is made of natrium silicate (Na2SiO3.2H2O). Factors related to selection of mixed composition with respect to fire such as the easiness in processing or coating as well as the optimum weight of coating per m2 are investigated. Experimental method is used in this research with equipment used in this experiment include Fire Propagation Test Apparatus (based on JIS A 1321, 1994, # 605). Experiment is done on Borneo and Red Meranti Wood and comparison is done on the result of test undertaken on these types of wood which are treated with siliceous based fire retardant materials. Investigation also reveals that the more natrium silicate absorbed by the wood will increase the temperature rise (td e) and smoke developed index. Experiment on mixture composition of 1 : 1 on both woods has proven it. The best mixture of siliceous based fire retardant against fire while ensuring ease workmanship is under the ratio 7 : 1 up to 10 : 1, with the layer optimum weight per m2 is approximately 0.7 kg. Using this type of fire retardant has proven the increase in the quality of Borneo wood and Red Meranti wood from quality class 4 (Semi fire retardant) to become quality class 2 (Semi non combustible).

FRP strengthened SHS beam-column connection under monotonic and large-deformation cyclic loading

Structural behaviour of CFRP strengthened beam-column connections under monotonic and cyclic loading

Tapered reduced deep beam connection for long span steel moment frames

X-braced Frames(XBFs), one of the most prevalent lateral load-resisting structures, has low energy dissipation and ductility. This study investigates the behavior of a single-story, single-span X-braced frame equipped with a Vertical Link Beam (XBF-VLB) under monotonic and cyclic loading using the nonlinear finite element technique in the Abaqus software and validated with experimental data. The VLBs were positioned where the bracing members were connected to the beam in double, single, and wide forms. The impacts of the length, depth, and the number of links, stiffeners, and other VLB section parameters were assessed. The A36 steel ductile damage method (DDM)estimated the damage of the main structural members, such as bracing members. The results revealed that X-braced frames with single, double, and wide form Vertical Link Beams (XBF-VLBs) performed better under cyclic and monotonic loading than X-braced frames without Vertical Link Beam (XBFs). Likewise, because the bracing members did not buckle inthe XBF-VLB specimens, there was no rapid loss in the stiffness and strength of the X-braced frames. Also, theresults of the cyclic loading of the XBF-VLB specimens demonstrated that no rapid drop in stiffness or strength was detected due to no buckling of the bracing members under the cyclic loading, as was the case with the monotonic loading. Additionally, compared to the XBF specimens, the drifts corresponding to the first plastic hinges of the XBF-VLB specimens show that the bracing members experienced nonlinear deformation at greater drifts, with the plastic hinges created in them at bigger displacements. According to the cyclic loading results, the VLB also reduced Von Mises stress and damage in the bracing members of the XBF-VLB specimens. Moreover, theultimate von Mises stress reduction in the bracing members of the models with VLBs equals 33%, which prevents buckling.

The 1994 Northridge earthquake that struck Los Angeles, California, revealed structural failures in steel beam-column connections of building frames that occurred prior to the formation of plastic hinges in the beams. To prevent similar failures in the future, ANSI/AISC 358-16/358s1-16[2] introduced prequalified steel connections, which were later adopted into the Indonesian steel structure standard, SNI 7972:2020[1]. This study aims to investigate the influence of bolt diameter, end-plate thickness, and beam flange thickness on the moment capacity of prequalified and modified 4ES-type steel beam-column connections. The analyzed models consist of standard and modified 4ES-type connections based on SNI 7972:2020, using IWF beam profiles of 300x150, 350x175, and 400x200. Bolt diameter and end-plate thickness were varied to achieve connection moment capacities exceeding the beam’s plastic moment capacity and satisfying the required plastic hinge rotation. The moment capacity and ultimate plastic hinge rotation were calculated in accordance with the provisions of SNI 7972:2020[1]. The results of this study indicate differences in moment capacity and rotation due to variations in steel yield strength (Fy) in both standard and modified 4ES-type connections. A relationship was established between the minimum end-plate thickness (Tp), bolt diameter (Db), and beam flange thickness that enables the connection to exceed the plastic moment of the beam and meet the required plastic hinge rotation for special moment frames. These findings are useful for developing steel frame designs that satisfy the criteria for seismic-resistant special moment connections. Additionally, the use of high-strength steel (Fy = 413 MPa) is investigated to meet the requirements of high moment capacity and plastic hinge rotation exceeding 0.04 radians in high-rise earthquake-resistant buildings.

The unexpected local damage may happen in the beam column connections of steel structures under lateral loads, since the connection is the focal point. Adopting reduced beam section (RBS) is an innovative method to dissipate the energy of such structures since it will enable a plastic hinge to be formed in the beam portion, thus reducing large stress concentration in the connection. Also, the formation of plastic hinge will satisfy the seismic criteria of strong column and weak beam combination. This paper focuses on analyzing the efficiency of cruciform connection fabricated with RBS. The structural components comprise of standard I section beam and column connected through welds. Finite element method is applied and model is created for cruciform connections in which different RBSs are used. The models are validated using experimental analysis applied on the specimen. The monotonic load is gradually applied at the two ends of the beams and moment rotation behavior is established. Similar behavior is studied for the RBS model and double reduced beam section (DRBS) as well. The effective connection stiffness is identified for the different models under consideration. It is observed from the results that RBS and DRBS can sustain large inelastic strains besides limiting stress concentration in the connection.

The log building industry favors simple to install mechanical connections between log layers, also referred to as log courses, to facilitate fast and efficient construction. In active seismic regions, lag screws are commonly used: however, research is lacking on how these connections between log courses perform in monotonic and reverse-cyclic loading scenarios. For the current study, 406-mm-long logs were used to fabricate connection test specimens in a single-shear configuration to mimic a typical lag screw layout used in log shear wall construction. The intent of this study was to develop baseline data on these connections to relate log connection performance to full-scale log shear wall performance. A preliminary study of four commonly used lag screws of different sizes was conducted to assess the monotonic performance within log connections. Predictions of design capacities were calculated using the National Design Specification for Wood Construction which is based on derived equations from the European yield model. Predicted NDS design capacities were compared to experimental data. Design recommendations for deriving appropriate fastener spacing were provided along with fabrication parameters that were based on observed failure mechanisms. Tested connections exhibited high ductility, which is considered a positive attribute for seismic resistance, although reverse-cyclic tests revealed failures due to low-cycle fatigue of the lag screws, leading to prevalent cyclic stiffness degradation as displacements were increased.

This paper proposes a new beam to column connection which has slit dampers to increase ductility and moment capacity of structures. After Northridge and Kobe earthquakes, many researchers have tried to achieve more ductile connections. Ductility of connections causes to dissipate more energy before failure of connections. Also, some researchers have tried to find methods that plastic hinge occurs out of the beam to column connection zone. The proposed detail connects beam to column by two I-shape slit dampers. One experimental specimen of the proposed connection was tested under cyclic loading. Based on the experimental results, the connection has high seismic performance and rotational capacity more than 0.04 radians. Also, the slit damper connection has more moment capacity than other common connections and indicates a good hysteretic behavior. Experimental observations showed that no cracks and fractures occurred in welds and high energy absorption of the slit dampers prevented damages of other parts. Also, local buckling didn’t occur on the flanges and web of the beam. The column and beam remain in elastic state. Some numerical models were made in ABAQUS software. Analysis results had good agreement with experimental results and showed high energy dissipation and ductility in the proposed connection.

Bending moment capacity and failure mechanism of caisson foundations under monotonic and cyclic loading in clay

Numerical and experimental study on the behavior of drilled flange steel beam to CFT column connections

Joints behaviour of through steel beam to composite column connection: Experimental study

Experimental investigation on lateral performance of southern pine nailed connections under monotonic and cyclic loading