Internal Force Analysis Research Articles

Enhancing the lateral performance of Chuan-dou timber frame infilled with vertical wood panels

Chuan-dou timber frame system represents a prevalent form of traditional wooden architecture, extensively employed in Southwest China. The wood infilling wall stands as a primary manifestation of infill wall construction in Chuan-dou timber frame system, and the existence of infilled walls significantly impacts the lateral behavior of Chuan-dou timber frames. In this paper, the internal force analysis of the timber frame specimen infilled with vertical panels (TFVP) had been undertaken by the credible finite element model, elucidating the detailed enhancement mechanism of wood vertical infilled panels on the lateral performance of the timber frame. 10 models with diverse geometric parameters were formulated to investigate the influence of geometric factors on the vertical panels, including width and thickness. The research findings showed that the presence of Dijiaofang and wood infilled walls could result in a substantial enhancement in the load capacities and initial lateral stiffness of the timber frames. Among them, the enhancement effect of Dijiaofang comes from half-tenon joints (HTJs), while the reinforcement of wood vertical infilled panels arises from the interplay between adjacent panels, as well as the squeezing and friction behavior between the infilled wall and Chuan-dou timber frame. Furthermore, the parametric analysis indicated that the geometry of vertical panels has discernible effects on the lateral performance of TFVP specimens.

Evaluasi Rasio Kapasitas Plat Lantai Jembatan Pangwa Berdasarkan Mutu Beton Aktual

This article reviewed the effect of decreasing quality of concrete in the vehicle deck on Pangwa bridge located in Trienggadeng, Pidie Jaya district, Aceh Province. The bridge deck was planned to use concrete with a quality of 30 MPa, however in practice, it was estimated that only 18.8 MPa was achieved. Based on the actual concrete quality, this article reported a reanalysis of the bending and shear capacity ratio. Structural analysis was carried out using SAP2000 software referring to engineering design data. The stages include modeling the bridge as a space frame steel construction with a deck using reinforced concrete material, loads calculation, internal force analysis, and checking the structural capacity. Load calculations and load combinations refer to the standard Loading for Bridges (SNI 1725: 2016). The bridge deck was analyzed as a one way slabs using D16-150 reinforcement with steel grade fy = 320 MPa. The loads taken into structure analysis include: self weight, additional dead load, truck load, and wind load. Based on the loads on the bridge, it is estimated that the possible forces arising from certain conditions are calculated based on the ultimate load combination of Strength-I, Strength-II, Strength-III, Strength-IV and Strength-V according to the provisions of SNI 1725-2016. Based on the results of the structural analysis recapitulated from the value of the load combination, the maximum and minimum moments were 388.68 kN.m and -391.22 kN.m while the maximum shear force were 169.60 kN. The planned bending capacity was 396.303 kN.m (design) and was achieved at 365.568 kN.m (actual) or 7.75% less than the ultimate moment. The pons shear force arising on the bridge deck was Vu = 169.6 kN with pons shear capacity, ØVn = 874.895 kN in the design data and was achieved by 703.811 kN (actual). Based on the results of these calculations, it can be concluded that Pangwa bridge still meets the level of safety for the use as a vehicle traffic lane.

Optimization of Technical Calculation of Precast Wall Application for Kawo Secondary Canal Improvement in Sempor Irrigation Area, Kebumen, Central Java

This study aims to perform technical calculations using precast lining in the repair of secondary channels. The planning data used included a concrete grade of fc 18.68 MPa and a reinforcement grade of fy 500 MPa. The service condition analysis was carried out by taking into account the loading during the most critical condition, where the channel is empty and active soil pressure and external water pressure are the main loads. The fixed load calculation was the main focus, where the active earth pressure (PD) was calculated by considering the soil-specific gravity, soil shear angle, and soil coefficient. The calculation results show that the PD reaches 12.24 kN, which gives an idea of the load that the structure has to bear. Furthermore, the internal force analysis provides a deeper understanding of the moments occurring at specific points in the structure. For example, the maximum negative moment at point A was calculated by considering the moments due to fixed load and transient load, which reached 12.73 kNm. This research contributes to improving efficiency and safety in the application of precast lining for secondary channel improvement.

Analysis of 2D Beam Structure Using the Matrix Method Using the PTC Mathcad and SAP2000 Applications Article Sidebar Published: Jun 30, 2024 DOI: https://doi.org/10.37253/jcep.v5i1.9208 Keywords: Struktur Balok, Matriks kekakuan, PTC Mathcad, SAP2000 Main Article Content

Concrete beam structure that functions as an element to support bending loads and shear forces. The PTC Mathcad application software has a built-in matrix method, which makes it very easy to use to create simple structural analysis programs using the stiffness matrix method. The aim of this research is to create a simple analysis program using the PTC Mathcad application to analyze 2D beam structures using the matrix method and compare the analysis results with the SAP2000 application. PTC Mathcad and SAP2000 analysis will produce joint reaction values ​​for force, moment, and joint displacement for each beam model. Based on the results of the comparative analysis of internal force results produced from the PTC Mathcad application and the SAP2000 application, it was found that the

Analysis of Diaphragm Force on Reinforced Concrete Building Structures with Horizontal Irregularities of Diaphragm Discontinuity

The diaphragm plays a crucial role in distributing seismic forces within buildings during earthquakes, affecting both regular and irregular structures differently. This study investigates the seismic behavior of diaphragms in various building geometries resembling the letters I, T, L, and O, focusing on their influence on structural performance and reinforcement requirements. Using analytical methods, diaphragm seismic forces, slab shear stresses, and internal forces were calculated for a sample of buildings with different geometrical irregularities. The study reveals significant differences in diaphragm earthquake forces between regular and irregular buildings, with irregular geometries exhibiting distinct patterns of shear stress distribution. Particularly, the building with an L-shaped plan and concentrated stress points showed the highest maximum shear stresses in both orthogonal directions. Analysis of internal forces—axial, shear, and moment—highlighted varying reinforcement needs among the studied buildings. While axial and shear forces necessitated minimal additional reinforcement across all structures, moment forces indicated substantial reinforcement requirements, particularly in the L-shaped building. These findings underscore the importance of tailored diaphragm design strategies for buildings with irregular geometries to mitigate potential structural vulnerabilities during seismic events. The study contributes insights into optimizing diaphragm design practices and emphasizes the need for further research in this critical area of structural engineering.

Critical size and internal force analysis of tendril-inspired spontaneous Helicalization mechanism

Tendrils initially exhibit straight morphologies before gradually transforming into helical conformations during longitudinal growth. Tendril-inspired helical structures possess advantageous physical properties and functions including versatile morphologies, adaptability, enhanced strength, and scalability. With advancements in nanoscience and nanotechnology, helical architectures across various length scales have been discovered or artificially synthesized. However, the fundamental mechanisms underlying the formation and evolution of helical structures remain elusive. This lack of mechanistic insight has impeded the controlled design and fabrication of helical structures, especially three-dimensional functional devices with integrated helical motifs. Here a mechanical model is systematically proposed for the spontaneous formation of the helical structures, based on the hypothesis of decoupled curling and warping phases. Applying nonlinear elasticity theory, a detailed analysis of the energetics and thermodynamics is presented, accounting for the large deformation that may emerge during planar curling. Additionally, differential relations between internal forces and associated displacements induced by bending and twisting of a slender curved beam under out-of-plane loading are derived, obtaining solutions via Laplace and inverse transforms. The theoretical solutions closely match ex- perimental evidence from shape memory polymers. Furthermore, the theoretical model is utilized to guide the fabrication of the smart helical antenna proposed in our previous work, and discuss the influence of configuration changes on the electromagnetic properties. Elucidating these fundamental mechanisms will facilitate the development of next-generation technologies exploiting helical architectures for diverse applications including flexible electronics, optics, and soft robotics.

Correlation Analysis of Tunnel Deformation and Internal Force in the Earthquake Based on Tunnel Inclination

An increasing number of studies have shown that the seismic response of shield tunnels differs from that of aboveground structures. While the seismic response of aboveground structures is mainly influenced by the peak acceleration and frequency of the earthquake, the seismic response of shield tunnels is more influenced by the ground displacement due to the surrounding soil layers. In this study, it is not appropriate to follow the seismic concept of aboveground structures. Dynamic time-history analysis is a powerful and effective method to study the seismic response of tunnels in the typical subway in this paper. The analysis results show that the overall levelling of the tunnel will not affect the tunnel too much, and the seismic response of the tunnel is mainly related to the relative displacement of the ground around the tunnel. The analysis results show that the internal force of the tunnel and the tunnel inclination have a good linear relationship, and the tunnel inclination can be used to measure the magnitude of the seismic response of the tunnel. In the seismic design of shield tunnels, the inclination of the tunnel can be taken into account to evaluate the change in the internal forces of the tunnel during earthquakes, which avoids the need for complex dynamic time-history analysis and greatly improves the efficiency of the seismic design of shield tunnels.

Ispitivanje poprečne unutarnje sile sandučastog nosača primjenom principa varijacije energije

This study investigated the transverse internal force of a box girder with a trapezoidal cross-section under eccentric loading. The effects of the box girder distortion and frame shear difference on the transverse internal force were considered. An energy variation method based on the minimum potential energy principle was adopted for transverse internal force analysis of the frames. The variable shear difference of the top slab was considered an unknown quantity, and a fourth-order governing differential equation was established. The transverse bending moment of the frame was obtained by solving for the shear difference. Two examples were used to verify the proposed method and analyse the differences between the transverse internal force results calculated using different methods. The effect of the distribution of the box-girder distorted transverse bending moment on each slab was investigated for various stiffness ratios. The results showed that the transverse internal force of the box girder calculated using the proposed method agreed well with the finite element results, with a maximum error of less than 9.68 %. When the stiffness ratio of the box girder increased, the distribution of the distorted transverse bending moment on the top slab increased, whereas that on the bottom slab decreased.

Magnification factor for pile internal forces of pile‐supported wharves under bi‐directional ground motions

AbstractIn order to determine the pile internal forces of wharf under simultaneous seismic excitation in orthogonal horizontal directions with ease, the total internal forces can be obtained by multiplying the pile forces of two‐dimensional model under transverse earthquake loading with a magnification factor. The factors were computed from the seismic response of wharves having various aspect ratios (length to width) and eccentricity ratios when subjected to 30 pairs of bi‐directional earthquake records. Mean magnification factors and their corresponding dispersion are presented for all ground motion ensembles. The influence of aspect ratio and eccentricity ratio is evaluated and discussed. It is concluded that the magnification factor can be expressed as the function of aspect ratio and eccentricity ratio, and follows lognormal distribution. The proposed equation of magnification factor can be an alternative for internal force analysis of wharves under bi‐directional ground motion.

Experimental clarification of the lateral performance of squat mud infill walls in the timber frames of traditional Japanese residential houses

This paper presents the experimental results of squat mud infill walls with three different height aspect ratios in the timber frames of traditional Japanese residential houses. The deformation and failure characteristics, lateral load-carrying mechanism, and influence of the height aspect ratio on the lateral behavior of squat mud walls are investigated. We observed that when the height aspect ratio of the mud wall is less than 0.5, the initial failure is dominated by corner crushing rather than by shear failure. The lateral stiffness of the squat mud wall is positively correlated with the wall height, whereas the drift angle corresponding to the bearing capacity exhibits an inverse relationship with the wall height. For a height aspect ratio less than 0.3, the internal deformation of the squat mud wall is primarily driven by the deformation angle related to corner crushing and sliding. However, when the height aspect ratio increases to 0.5, the rotation angle increases significantly. The transformation of the deformation characteristics and internal force distribution of the squat mud wall depends on the interplay between the wall height aspect ratio and friction coefficient between the mud wall and timber frame. Drawing from comparative experiments and internal force analysis, the lateral resistance of the squat mud infill wall can be separated into two groups of elements: Qc and Qc’, stemming from the corner compression between the mud wall and adjacent timber frame or internal timber laths, respectively, which exhibits a significant positive correlation with the wall height; Qf and Qg, attributed to the frictional force of the protruding ends of bamboo laths and the gravitational force of the squat mud wall, respectively, which exhibit a consistent behavior unaffected by alterations in the wall height.

Fire research of joint between special-shaped CFST column and U-shaped composite beam

The steel-concrete composite joint plays an important role in the building structure of transmitting load and maintaining structural stability, and the research on fire performance of composite joints is significant. The special-shaped concrete-filled steel tube (SCFST) column and U-shaped steel-concrete composite beam (USCB) have good fire resistance which is proved by authors' previous fire tests. Therefore, the fire performance of the joint between SCFST column and USCB, the temperature distribution, failure mode, fire resistance, and internal force distribution of the joint under fire are investigated based on the fire tests results of column and beam component. The results showed that the temperature of the joint zone is lower than that of the non-joint zone, which ensured that the strength and stiffness of the joint zone are higher than that of the non-joint zone (beam and column). Then the two failure modes including beam failure and column failure occurred in the composite joint in fire conditions. Furthermore, the internal force analysis indicated that internal force redistribution happens during the elevated temperature. The parameter analysis expressed that fire resistance decreases with the increase of load ratio and the beam-column moment ratio and increases with the increase of the beam-column stiffness ratio and the fire protection layer thickness. Finally, the high-temperature calculation formula for the bearing capacity of beam-column joint was proposed.

Internal force and damage analysis of foundation of steel–concrete wind turbine tower

The internal cavity of the foundation of a steel–concrete composite wind turbine tower (WTT) is designed to facilitate prestressed construction. The load-bearing mechanisms of this type of foundation are different from those of ring-type and anchor-type foundations commonly used in steel WTTs. Based on a real project, an integrated model of a prestressed tower–foundation–ground was built using the finite-element software Abaqus. The internal force and damage in the foundation of a steel–concrete WTT under extreme load conditions were studied using the static loading method. Under extreme load conditions, prestressed reinforcements were found to have little impact on the local pressure at the anchor end of the foundation. Prestressing the reinforcement effectively prevented concrete cracking and tower deformation. For areas experiencing extreme loads on both sides, simplified calculations for stress and reinforcement can be performed using calculation formulae for the bracket.

Motor control similarity between speakers saying "a souk" using inverse atlas tongue modeling.

Finite element models (FEM) of the tongue have facilitated speech studies through analysis of internal muscle forces indirectly derived from imaging data. In this work, we build a uniform hexahedral FEM of a tongue atlas constructed from magnetic resonance imaging data of a healthy population. The FEM is driven by inverse internal tongue tissue kinematics of speakers temporally aligned and deformed into the same atlas space, while performing the speech task "a souk" allowing muscle activation predictions. This work aims to investigate the commonalities in tongue motor strategies in the articulation of "a souk" predicted by the inverse tongue atlas model. Our findings report variability among five speakers for estimated muscle activations with a similarity index using a dynamic time warp function. Two speakers show similarity index > 0.9 and two others < 0.7 with respect to a reference speaker for most tongue muscles. The relative motion tracking error of the model is less than 2% which is promising for speech study applications.

Surrounding rock pressure calculation based on time functions and stress release rate determination of deep soft rock tunnel: taking Zhonghe Tunnel as an example

On the basis of the Zhonghe Tunnel project of the An-Lan Expressway, the objective of this study was to determine the appropriate method of calculating the steel arch load and stress release rate during numerical simulation. First of all, based on the monitoring results of six similar tunnel sections where the surrounding rock exerts pressure on the steel arch, using time functions, the rock pressure time history curve could be fitted, two formulas for calculating stable rock pressure in deep tunnels were compared, and the calculation model suitable for the Zhonghe Tunnel project was constructed. Then, a simulation of the Zhonghe Tunnel was performed using Flac3D, and stress release was simulated using the Mana method. By comparing the surrounding rock characteristic curves and the initial support characteristic curves under different stress release rates, the impact pattern of the stress release rate on the support load was summarized, and an appropriate excavation stress release rate was determined based on the stable rock pressure value calculation. It was found that the Zhonghe Tunnel rock pressure calculation model could better depict the change in rock pressure over time based on the empirical formula and Weibull time function. A prediction of the steel arch load of the Zhonghe Tunnel could be made using this method, and the stress release rate of the numerically simulated rock excavation was determined to be 0.5. This study thus provides a basis for the future internal force analysis and support parameter design of support systems.

Geometric nonlinear analysis of dielectric layer based on concave paper-cut structure with zero Poisson’s ratio

When the sensor works in a limited environment, its accuracy is easily affected by unnecessary strain loss. The key to improve accuracy is to reduce the transverse strain of the dielectric layer structure. It is an innovative technology to construct zero Poisson’s ratio dielectric layer to limit the lateral strain of dielectric layer under normal pressure. The porous metamaterial dielectric layer with zero Poisson’s ratio is constructed based on the paper-cutting theory. The equivalent nonlinear mechanical model is established by use of Bernoulli Euler beam theory and energy method. The analytical expressions of equivalent Poisson’s ratio and equivalent Young’s modulus are given, and the necessity of considering geometric nonlinear large deformation is revealed. An improved variable step iterative method is proposed in order to solve the problem of equivalent internal force analysis caused by geometric deformation nonlinearity. The key of this method is to determine the displacement at the free end under the premise of considering the nonlinear superposition of the rigid body motion of the curved bar of the metamaterial. Based on the equivalent nonlinear mechanical model, the structural deformation characteristics of the dielectric layer structure in the linear small deformation stage and the nonlinear large deformation stage are analyzed. The results of theoretical, finite element simulation and experimental research reveal the necessity of considering geometric nonlinear factors in the practical application of the structure, which means that the foundation is theoretically and experimentally laid for the design of porous elastic dielectric layer of flexible capacitive pressure sensor.

A Comparison of Load Distribution Methods at the Node and Internal Force Analysis of the Lattice Beam Based on the Winkler Foundation Model

As a new type of retaining structure, lattice beams with tie-back anchor cables have been increasingly used in slope reinforcement and have achieved improved prevention effects. However, the simplified load distribution method (SLDM) at the node, which is the theoretical basis of internal force analysis for lattice beams, is not perfect at present. An alternative new load distribution method (NLDM) at the node based on the force method for the lattice beam was therefore introduced in this paper. Taking into account the loads acting on other nodes of the beams in both directions and according to the static equilibrium condition and deformation compatibility condition at the nodes, NLDM assigns the loads acting on the nodes to the cross beams and vertical beams, respectively, by constructing and solving a system of linear equations. In order to verify the superiority of NLDM, a case of slope reinforced by a lattice beam was introduced in this paper, and the load distribution of the nodes under the design condition was carried out based on both methods. Then, the deflections at the nodes of the lattice beam resting on the Winkler foundation, loaded with the known loads, were analyzed by the superposition method. The results of the deformation analysis showed that the deflections at the same nodes of the beams in both directions based on NLDM were almost equal, thus demonstrating the superiority of NLDM in terms of deformation compatibility. In addition, a comparative analysis of the theoretical bending moments of the lattice beam under the design and the actual working conditions based on both methods was also carried out. The results of the bending moment analysis showed that the bending moments of the cross beam differed significantly in the middle third of the beam length, while the bending moments of the vertical beams differed significantly at the beam sections where the maximum bending moments are located, and the theoretical bending moments under the actual working condition were in relatively good agreement with the measured values. Consequently, NLDM for the lattice beam was self-consistent in terms of the deformation compatibility at the node, and therefore the introduction of this new method provides an important theoretical basis for the accurate internal force analysis of lattice beams.

Internal force analysis of beams on elastic foundation using differential evolutionary optimization algorithm based on hybrid mutation technique

The paper presents the Finite element method (FEM) that calculates the internal force and the displacement of beams on elastic foundation in the case of the uncertainty input parameters described in terms of the number intervals. Using the interval function optimization algorithm combined with the FEM to determine the internal force values of the span reinforced concrete beam structure. This study applies the hybrid differential evolutionary optimization algorithm combined with FEM interval functions to determine the required internal force results of reinforced concrete beams placed on an elastic foundation. The calculation process is programmed using Maple.17 software to determine the displacement output and the resulting internal force in the beam. To check the correctness of the program calculated on Maple.17, the input declared dataset corresponds to the central values of the interval numbers and is recalculated by SAP2000v21 software, then evaluates the results error of internal force on the beam under consideration.

Feasibility of two-storey substructures to equivalently investigate behaviour of multi-storey steel frames

Disproportionate collapse of steel frame is often an indicator of the overall behaviour of multi-storey building. The corner column failure is followed by deformation of all beams and columns above removed columns and redistribution of the load carried by the corner columns. Although several experimental studies of disproportionate collapse have been carried out after corner column loss, most of them only focused on the single-storey substructure, while inevitably ignoring the interaction between the storeys in the multi-storey frames (Vierendeel action). In this study, the performance of a two-storey substructure after corner column loss was experimentally studied and a corresponding numerical model was established utilizing LS-DYNA. FE model was validated and used to further study the effects of the proposed boundary assumptions, load redistribution of multi-bay steel frames, and number of bays and storeys on load resisting mechanisms. The results indicated that Vierendeel action is essential in resisting disproportionate collapse, with a contribution of 43% to the peak load. For a multi-storey frame with more than two storeys, the normalized load resistance of each storey is approximate. However, due to Vierendeel action, further internal force analysis indicates that the load resisting mechanisms are different in each storey. The two-storey substructures for understanding the disproportionate collapse behaviour of multi-storey steel frames under corner column loss are highly recommended by the parametric analysis.

Analysis of Internal Forces and Structural Dimensions on the Variations of Courtroom Placement of DPRK Building

The construction of state buildings is caused by the increased mobility of needs. One of them is the DPRK building that wants the placement of the plenary session room to be on the 2nd or 3rd floor. This study aims to evaluate the internal style and behavior of the structure that arises due to variations in the placement of the plenary session room so as to produce the most optimal choice of courtroom for the most effective structural dimensions. Structural analysis was carried out using the ETABS program by carrying out 4 variations of courtroom placement, namely Varian 1 (the courtroom is located on the 1st floor), Varian 2 (2nd floor), Varian 3 (3rd floor), and Varian 4 (4th floor). Variant 2 (DED) is a reference sourced from the DED from the planning consultant. The seismic load analysis used is the method of Dynamic Analysis of Response Spectrum Variety. Parameters reviewed are internal forces (axial, normal, and moment) and structural behavior (story displacement, displacement between floors, nominal base shear forces, and vertical irregularities). The calculation analysis refers to the latest standards, namely SNI 1726:2019, SNI 1727:2020, and SNI 2847:2019. The results of this study indicate that the greatest internal force values occur in Variant 4. The level displacement and the displacement between floors increase in the variant with the smaller structural element dimensions. The level displacement of the X and Y axes has increased in Variant 3 and Variant 4, and has decreased in Variant 1. The nominal base shear force value has decreased for Variants 1, 3, and 4 against Variant 2 (DED) because it has smaller structural dimensions. . All modeling variants experienced soft stiffness irregularity type 1A, excessive soft stiffness irregularity type 1B, and heavy (mass) irregularity type 2. Variant 1 was chosen as the variant with the best courtroom placement, because it met the requirements for earthquake design.

Internal Force Calculation Method for a Complex Curved Beam Under a Vertical Load

In design, curved beams are popular owing to their aesthetic appearance. They are found to be in a state of coupled bending, shear and torsion when subjected to vertical loads. This complex behavior makes it difficult to perform force analysis in structural design. In this article, a set of equations are derived to calculate the internal forces at any position of a curved beam that consists of two orthogonal straight segments and one circular arc axis segment under a vertical load based on the force method. To simplify the calculation in practice, a simplified internal force analysis method is further developed by transforming the arc section into an equivalent straight beam model. The simplified formula is derived by fitting the internal force of 729 different curved beams, and it can be used quickly and accurately for hand calculation of internal force in a curved beam. Finally, the effectiveness of the proposed methods is verified by three engineering examples. The results show that the proposed force method can reasonably estimate internal forces at different locations of a complex curved beam, and the proposed simplified method can provide a convenient and practical approach to calculating the internal force distribution of curved beams.