Internal Force Analysis Research Articles

A Simple Prediction Model for Mechanical Response of Lined Tunnels Incorporating Yielding Elements

The lining incorporating yielding elements has been proved to be the most effective solution for tunneling through severe squeezing ground. Unfortunately, there has not been a well-organized method to transfer its beneficial effects into the practical tunnel design. This study aims to provide an analytical model for predicting the behavior of yielding lining supported tunnel. The internal force analysis of the lining is first carried out to determine the optimal installation positions of the yielding elements. Second, the lining incorporating yielding elements is processed as a simplified shell using the equivalent deformation principle. The equation for calculating the elastic modulus of the simplified shell is presented. The analytical solutions for the tunnel displacement and lining pressure are provided in the viscoelastic Burgers rocks, where the installation delay of the lining and the tunnel face advancement effect are taken into account. The proposed analytical model is applied in the Saint Martin La Porte access adit of Lyon-Torino Base tunnel, where the yielding lining was employed. The analytical result provides a good prediction of the time-dependent tunnel convergences in the Saint Martin La Porte access adit. Finally, a comprehensive parametric investigation is performed, including the influences of installation time of yielding lining, yield stress and length of yielding elements. Some inspiring results for the tunnel design are provided.

Analysis of Internal Forces and Deformation for a Single Pile in Layered Soil Based on the p-y Curve Method

The p-y curve method can be used to describe the stress–strain relationship of soil under elastic, elastoplastic, and plastic states, and is more accurate than other methods in dealing with the nonlinearity of pile–soil interaction. However, the p-y curve method also has several limitations. First, when constructing the p-y curve, undrained shear strength Cu is taken to be constant, and the diversity of soil layers around the pile side are also not considered. Second, in the analysis of the internal forces and deformation of the pile, the influence of the vertical load from the top of the pile and the self-weight of the pile, are both ignored. Third, in the analysis of internal forces and deformation, the pile side soil is set equivalent to a homogeneous soil layer, and the layering of the soil is not considered at all. In order to study the nonlinear problem of internal forces and deformation of a single pile in layered soil in greater detail, this paper analyzes a calculation model based on Wang’s calculation model, and compares several commonly used p-y curve calculation models. An internal force and deformation analysis model for a laterally loaded single pile, that explicitly considers the second-order effect is then established, by considering the differences between p-y curves of different soil types, as well as the change in Cu with depth. The differential equation of pile deflection for a single pile in layered soil is also presented, together with the corresponding finite differential solution algorithm program. This model was validated using a horizontal load test of a pile, and comparison of the calculated results with the measured results shows that the method outperforms existing p-y curve methods for deformation and internal force analysis of horizontally loaded piles.

Theoretical Analysis of Deformation and Internal Forces of Used Piles Due to New Static-Pressure Pile Penetration

Evaluation of the impact of new static-pressure pile penetration on used piles is vitally important for the reutilization of the used piles. The cavity expansion theory in semi-infinite soil is adopted to obtain the displacement field of the surrounding soil caused by new pile penetration, and then the displacement is applied to the used pile based on a two-stage method to analyze the deformation and internal force of the used pile. The effects of constraint conditions of the used pile, the pile rigidity and the soil modulus on the response of the used pile are considered. Meanwhile, numerical analysis is adopted to verify the effectiveness of the theoretical method. The influence of the distance between the new and used piles and the radius of the new pile is analyzed, and the measures to reduce the influence of new pile penetration on existing piles are proposed. The results show that the form of pile end only affects the deformation near the pile end. With the increase in pile diameter, the existing pile deformation gradually increases. As the distance between the existing pile and new pile increases, the existing pile deformation decreases significantly.

Dissipating the earthquake lateral base force of structure using sliding plate and link beam base isolation

Link beam and sliding plates is used to isolate structure against lateral base shear of the foundation due to earthquake forces, the link beam element made from steel wide flange act as a metallic damper, combined with sliding plates become as base isolation. Analysis with the Etabs program results in significant differences in internal moment, shear and axial forces between structures that using link beam base isolation and those without, as well as the results for drift and deformation of the structure. The first step of analysis is estimate the dimensions of the structural elements. Base on the loads of the structure, the lateral base force of the structure can be calculated manually, so that, by applying the dynamic balance equation, the size of steel wide flange that will be used as the link beam. can be found. Furthermore, the analysis of internal forces, deformation, and structural drifts are calculated using the Etabs program for structural systems that with or without base isolation. The both results are compared so that it can be concluded that by using the base isolation link beam there is a significant decrease in the magnitude of the internal forces, drift and displacement, so that by using this base isolation, the elements of the structure will be reduced significantly, and the cost of structure can be saved, the safety and comfort of the building can be further improved too.

Research on Static Test Verification Technology of the Connection Between APU and Fuselage of Civil Aircraft

This paper studies the static strength verification of the connection between APU and fuselage of large civil aircraft, which provides a verification method for the airworthiness verification of the connection between APU and fuselage. Based on the internal force analysis results of APU finite element, this paper selects the static test load, completes the design from the theoretical load to the test load, designs a set of APU dummy loading device to introduce the load to complete the static test. The finite element analysis model is verified by the test results. The verified finite element analysis, limit load and limit load static strength test are used to show the airworthiness compliance of the static strength of the connection between APU and fuselage.

Out-plane interaction behavior of partially buckling-restrained steel plate shear walls

Partially buckling-restrained steel plate shear wall (PBRSPSW) mainly involves a steel plate partially restrained by out-plane restraining members, which is convenient to be transported and installed. The energy dissipation ability of PBRSPSW can be adjusted by changing the number of the restraining members. This paper focuses on the interaction behavior between steel plate and restraining members in PBRSPSW. The buckling and out-plane interaction behavior of PBRSPSW are studied by the simplified analytic method. The out-plane interaction force acting on the partially buckling restraining member results from the tension action and extrusion effect of the steel plate. Furthermore, a simplified continuous trusses model considering the fully developed buckling mode of the steel plate is developed to simulate the out-plane interaction behavior in PBRSPSW. Based on the internal force analysis of the continuous trusses model, an out-plane interaction force equation of PBRSPSWs is derived. Additionally, experimental studies were carried out to investigate the out-plane interaction behavior of PBRSPSW. The test results indicated that the out-plane interaction force of the PBRSPSW rises with the decline of the unstiffened zone’s height-to-thickness ratio. The out-plane force at the corner and bottom regions are higher than that of other regions. Considering the influence of the plastic buckling of steel plate, the theoretical equation for calculating the out-plane interaction forces of PBRSPSWs is modified and verified with the test results.

Influence and Safety Evaluation of Underground Structure Construction on Adjacent Existing Subway Section

<p>In recent years, with the rapid development of subway and underground comprehensive pipe corridor, the problem of close connection between underground structure and existing subway section structure is often encountered in engineering construction. During construction, the newly built underground structure will disturb the stratum, easily cause the additional displacement deformation and internal force change of the existing tunnel structure, and then lead to safety accidents. Therefore, it is particularly important to analyze the influence and safety evaluation of the new construction on the existing subway structure. This paper takes the construction of new underground power pipe gallery close to the existing subway section as an engineering case. The influence of adjacent construction on the existing structure is analyzed by three-dimensional finite element method, and then the safety of the existing structure is evaluated through deformation prediction, internal force analysis and bearing capacity checking calculation, and some construction safety protection suggestions are put forward. It has a certain reference for similar proximity projects.</p>

Studi Struktur Portal Baja Gedung Workshop Alat Berat Di Balai Wilayah Sungai Sumatera VI Tahap II Dengan Metode DFBK dan DKI

Analysis of calculations and planning in steel structures there are 2 methods that are usually used, the methods are the method load factor and resistance design (DFBK) and the method allowable strength design (DKI). The method DFBK is a method that takes into account the working load multiplied by several safety factors so as to produce a factored load which is then used to calculate or plan a building, while the method DKI is a method that does not depend on the combined load factor in the calculation and in its planning, but uses stresses. permission which basically this method emphasizes the duration factor of the load that occurs on the structure. In this case study, the author aims to compare the method DFBK and so what distinguishes the two methods in a gable frame steel portal building. Both methods use the H-Beam 200.200.7.11 steel profile for the column, the I-WF 200.100.5.5.5.8 steel profile for the beam, and the CNP steel profile 100.50.5.7.5 with internal force analysis on the steel portal carried out with the program SAP 2000 with loading in accordance with SNI 1727-2020 and the results of the program SAP 2000 taken the largest moment, shear and axial for the calculation of the steel structure portal. Based on the results of the calculation of the deflection of the method DFBK of 2.4 cm, the bolts used were 10 bolts and the base plate thickness was 15 mm. While the method DKI of deflection is 2.1 cm, the bolts used are 6 bolts and the base plate thickness is 14 mm. Based on the results of the study and the conclusion that the deflection of the method DKI is smaller than the method DFBK, the bolt requirements and base plate thickness of the method DFBK are closer in terms of construction, so the method DFBK is safer and stronger.

Simulation and Analysis of Internal Short Circuit Fault, Electromagnetic Forces and Thermal Analysis of Single Phase Transformer

Simulation and Analysis of Internal Short Circuit Fault, Electromagnetic Forces and Thermal Analysis of Single Phase Transformer

Theoretical Back Analysis of Internal Forces of Primary Support in Shallow Tunnels Subjected to Eccentric Loads

Theoretical Back Analysis of Internal Forces of Primary Support in Shallow Tunnels Subjected to Eccentric Loads

In‐Plane Instability of Parabolic Arches under Uniformly Distributed Vertical Load Coupled with Temperature Gradient Field

In civil engineering, arches, such as steel arch roofs and arch bridges, are often subjected to linear temperature gradient field. It is known that the in‐plane instability of parabolic arches is caused by the significant axial force. The arch under the linear temperature gradient field produces complex axial force, and so the instability of arches would be affected by temperature gradient field significantly. However, the analytical solutions of in‐plane instability of parabolic arches being subjected to the uniformly distributed vertical load and the temperature gradient field are not solved in the opening literature. In this paper, in‐plane instability of a fixed steel parabolic arch under linear temperature gradient field and vertical uniform load is analyzed theoretically. Firstly, the cross‐sectional effective centroid and effective stiffness of the cross section for arches under the linear temperature gradient field are derived. Secondly, the preinstability internal force analysis of the parabolic arch under the linear temperature gradient field and the vertical uniform load is carried out based on the force methods. Novel theoretical solutions for in‐plane instability load for fixed steel parabolic arches under the linear temperature gradient field and the vertical uniform load are obtained. It is found that the gradient temperature, slenderness, and rise‐span ratio have important influences on the critical in‐plane instability load of the shallow parabolic arch, while there is no significant effect on the deep parabolic arch.

Calculation and Analysis of Truss Internal Force Based on Beam Element

For plane truss structure, starting from the analysis of ideal truss model, the influence of tangential deformation and angular deformation on the secondary internal force of the truss is fully considered through Python program. It is obtained through analysis that: in the ideal truss model, the Pδ second-order effect causes the member to produce tangential deformation and angular deformation, resulting in secondary internal forces. Numerical analysis shows that due to the influence of secondary internal force, the axial force error of ideal truss model can reach 19.731% and the secondary shear force is almost all the members of the truss, and the secondary moment only appears at the support. The research results have important reference value for the engineering design and high-precision internal force analysis of truss structures.

Structural form-finding of bending components in buildings by using parametric tools and principal stress lines

This paper aims to provide an efficient and straightforward structural form-finding method for designers to extrapolate component forms during the conceptual stage. The core idea is to optimize the classical method of structural form-finding based on principal stress lines by using parametric tools. The traditional operating process of this method relies excessively on the designer's engineering experience and lacks precision. Meanwhile, the current optimization work for this method is overly complicated for architects, and limitations in component type and final result exist. Therefore, to facilitate an architect's conceptual work, the optimization metrics of the method in this paper are set as simplicity, practicality, freedom, and rapid feedback. For that reason, this paper optimizes the method from three aspects: modeling strategy for continuum structures, classification processing of data by using the k-nearest neighbor algorithm, and topological form-finding process based on stress lines. Eventually, it allows architects to create structural texture with formal aesthetics and modify it in real time on the basis of structural analysis results. This paper also explores a comprehensive application strategy with internal force analysis diagramming to form-finding. The finite element analysis tool Karamba3D verifies the structural performance of the form-finding method. The performance is compared with that of the conventional form, and the comparison results show the practicality and potential of the strategy in this paper.

Internal force analysis of the resistance unit of frame-truss composite wall

The frame-truss composite wall is a wall assembled by a certain number of resistance unit composed of outer frame and internal diagonal struts. As the primary energy dissipation unit of the system, the resistance unit should be studied in the perspective of internal force analysis. When the internal force of resistance unit is analyzed, the outer frame and the internal diagonal struts are regarded as composite members of reinforced concrete. According to the characteristics of resistance unit, the outer frame is regarded as a rigid frame and the internal diagonal struts are treated as struts hinging with the rigid frame and mainly subjected to axial force. So the simplified model is formed and it can be regarded as seven-degree statically indeterminate structure in mechanics. The internal forces of outer frame and internal diagonal struts corresponding to the constraint forces of simplified model can be calculated by solving the statically indeterminate problem. The ABAQUS model of resistance unit is established to simulated the performance so that the internal force can also be obtained in another way. The constrain force of simplified model and the internal force of ABAQUS model are comparatively analyzed and the results show a feasibility of simplified model. The phenomenon of cracks on diagonal struts and ultimate failure state of resistance unit are compared with the stress cloud of ABAQUS model to explains the reasonability of simplified model. The applicability of ABAQUS model is further stated by comparing the stress of longitudinal rebar on the most dangerous section between the simplified model and ABAQUS model for the resistance unit. This simplified model can provide a method to analyze the internal force of the resistance unit under external load, which also lays a foundation for the subsequent researches.

Analysis of Internal Force Based on In-situ Electrified Jacking of Transmission Tower

This paper mainly studies the law of the change of the internal force of the conductor and the climbing line with the number of rotation angles and the change of the jacking height during the construction process of the electric in-situ jacking of the transmission tower. First, the initial line type of the wire is calculated by the nodal line method to obtain the control point coordinates, and then the initial coordinates are repeatedly iterated through the Midas Civil finite element to obtain the final line type and the theory of the internal force change of the wire and the climbing line during the jacking process is calculated. law. Finally, combining the actual engineering case, the theoretical value and the actual value are compared and analyzed, and several conclusions are drawn.

Enhanced Simplified Method for Pseudostatic Analysis of Seismic Internal Forces in Rectangular Underground Structures

AbstractCurrent simplified analysis methods for rectangular underground structures subjected to earthquake action present in US design codes or analogous documents are based on the structure shear ...

Advanced Design of Block Shear Failure

This paper presents the behaviour and design procedure of bolted connections which tend to be sensitive to block shear failure. The finite element method is employed to examine the block shear failure. The research-oriented finite element method (RFEM) model is validated with the results of experimental tests. The validated model is used to verify the component-based FEM (CBFEM) model, which combines the analysis of internal forces by the finite element method and design of plates, bolts and welds by the component method (CM). The CBFEM model is verified by an analytical solution based on existing formulas. The method is developed for the design of generally loaded complicated joints, where the distribution of internal forces is complex. The resistance of the steel plates is controlled by limiting the plastic strain of plates and the strength of connectors, e.g., welds, bolts and anchor bolts. The design of plates at a post-critical stage is available to allow local buckling of slender plates. The prediction of the initial stiffness and the deformation capacity is included natively. Finally, a sensitivity study is prepared. The studied parameters include gusset plate thickness and pitch distance.

Dynamic instability zone analysis of laminated piezoelectric cylindrical shell with delamination under hygrothermal effects

To use effectively the shell in high-performance applications, analyzing the effect of hygrothermal effects on a piezoelectric delamination event is necessary. A laminated piezoelectric cylindrical shell with delamination is first established under hygrothermal effects, followed by an internal force analysis and an energy analysis of the shell. Then, a parametric vibration equation of the Mathieu for the shell is obtained by using the energy variation of the Rayleigh-Ritz method; later on, the harmonic balance method is employed to solve this equation. Finally, the effects of delamination parameters, geometric parameters, hygrothermal effects, and piezoelectric materials on the shell under uniformly distributed axial load are discussed.

Push-out behaviour of demountable injected vs. blind-bolted connectors in FRP decks

The main challenge for realizing competitive hybrid steel-FRP structures, such as bridges, carparks, is to make the steel and FRP components work together. In this study shear resistance, stiffness and ductility of three types of demountable bolted shear connectors are examined. Two blind-bolted M20 shear connectors and a novel, injected steel-reinforced resin (SRR) connection are selected to perform push-out experiments in web-core FRP decks. Failure modes of excessive bearing in FRP and bolt shear failure for blind-bolted and injected connectors, respectively, are identified. Nonlinear, highly detailed finite element (FE) models were also built and validated by results of the push-out tests to provide insights to the load-transfer mechanism. Analysis of internal forces and deformation through FE results reveals that blind bolted shear connectors provide high shear resistance and slip capacity thanks to the shear sleeves and catenary effects. The injected SRR connector shows distinct and centric load transfer owing to gapless design.

Design of Flying-Bird Type Cable Stayed Arch Bridge with Three-Leaf Rose Shaped CFST Arch Rib

According to the geometric figure of three-leaf rose curve, this paper puts forward a flying-bird type cable-stayed arch bridge with three-leaf rose curve shaped CFST arch rib, which has beautiful appearance and one bridge leads to three banks.The space cables are set between the three-leaf rose linear space arch ribs to resist negative bending moment, and the tie cables are set between the arch feet to resist positive bending moment. On the inclined pylon at the tail of the flying-bird type cable-stayed arch bridge, the stay-cables are arranged to balance the arch thrust, and the suspension-cables are arranged on the three leaf rose linear spatial arch ribs to hang the three fork bridge deck.The flying-bird type cable-stayed arch bridge with three-leaf rose linear CFST arch rib adopts spatial cable structure system, which has good structural stability.Combined with the actual project, the engineering parameters are designed, the Midas finite element analysis model is established, the internal force analysis and modal analysis are carried out, and the rationality of flying-bird type cable-stayed arch bridge with three-leaf rose linear CFST arch rib is verified.