Brace Angle Research Articles

LJF of thin-walled gapped uni-planar K-type tubular steel joints with collar under brace balanced axial loads

This paper investigates the efficacy of the collar plate in improving the Local Joint Flexibility (LJF) of thin-walled circular hollow section (CHS) K-joints under axial loads. Initially, a finite element model (FEM) was created and verified against data from 14 available experimental tests. Subsequently, an extensive series of 136 unreinforced and reinforced K-joints was simulated to analyze the influence of parameters such as collar plate dimensions (η and λ), brace angle (θ), and joint geometry (β, ξ, and γ) on the LJF factor (fLJF) and the fLJF ratio (χ). The FEMs incorporated plate-to-member contact and weld modeling. Findings indicate that the utilization of the plate reduces the fLJF by 73 %. Additionally, it was observed that plate length significantly affects the fLJF compared to plate thickness. While the impact of γ, θ, and ξ on χ is marginal, β, η and λ emerge as a noteworthy determinant of χ. Despite the pivotal role of fLJF in joint behavior, there exists a gap in studies and equations specifically addressing fLJF in collar-plate reinforced K-joints under axial loads. To address this gap, leveraging the FE results, a design equation is proposed. This equation is subsequently validated with high coefficients of determination and standards set by the UK Department of Energy.

Stress Concentration Factors of Concrete-Filled Double-Skin Tubular K-Joints

Tubular joints are important connecting parts of a welded steel tube structure. The S-N curves based on the hot spot stress (HSS) method are often used to evaluate the fatigue life of tubular joints in practical engineering. The stress concentration factor (SCF) is a key parameter to calculate HSS. In this paper, stress concentration tests of hollow-section and concrete-filled double-skin tubular (CFDST) K-joints were carried out, respectively, and then finite element models of K-joints considering the weld were established. The developed models were validated with the experimental results. The influence of key geometrical parameters, such as the diameter ratio of brace to chord β, the diameter to thickness ratio of chord γ, the wall thickness ratio of brace to chord τ, brace angle θ, and hollow section ratio ζ on the distribution and key position of SCFs along the weld toe, was discussed. Parametric studies were conducted to obtain the calculating equations for the SCF values of CFDST K-joints. The results demonstrate that infill concrete can effectively reduce SCFs along the weld on the chord. When the hollow section ratio was reduced to 0.317, the SCF was reduced by 77.2%. Notably, the SCF reduction rate was sensitive to γ and θ, with a decrease observed as γ increased. The hollow section ratio ζ had a less pronounced effect on SCF distribution patterns, but as ζ decreased, the chord’s stiffness improved, suggesting a potential approach to enhance joint performance. The distribution of SCFs is similar for joints of the same type but different geometric configurations. The innovatively integrated hollow section ratio in the CFDST design equation significantly simplifies and enhances the precision of SCF calculations for CFDST K-joints.

Between East and West: Mimar Kemaleddin and 'Ahmed Ratib Paşa Mansion'

This study focuses on the Late Period Ottoman Architecture through the summer mansion designed for Ahmed Ratib Paşa by Mimar Kemaleddin, built between 1900-1908. Ahmed Ratib Paşa Mansion’s classical planary discipline is oversailed with numerous cantilevers, balconies, and eaves placed on different levels and the angle braces that support them. On the façade, the eave adornments and the angle braces differ from classical decorative details and allude to an Ottoman Baroque past where curvilinear features are dominant. Floral Art Nouveau decorations in unique woodwork are used in all the architectural elements like balconies, windows and doors. In addition, the basket arches above the windows point to the building's affinity with the Art Nouveau movement in a rather striking fashion.
 Art Nouveau “Tarz-ı Cedid” showed up in Istanbul architecture, where almost all modes of Historicism were already represented, at the turn of the century. Although mostly applied by foreign architects, Art Nouveau was also practised by local ones who had received formal training. In Istanbul, where Art Nouveau buildings were common, the portfolio included mostly large scale urban residences such as apartment buildings, mansions and villas, countryside residences and office buildings. These buildings were favoured mostly by Ottoman high level bureaucrats, by the section of the society affiliated with the court, Levantine bourgeoisie and members of foreign missions. Considering Ahmed Ratib Paşa’s Western style and modern education, and likewise that of Mimar Kemaleddin's, it is not surprising that the former would wish for this new style in his residence and the latter would implement it. However, it is worth noting that it was also in the period where he was building Ahmet Ratip Paşa Mansion that Mimar Kemaleddin began forming his notion of “National Architecture”.
 Is it possible to consider Mimar Kemaleddin, who was influenced by Ottoman Baroque Architecture and designed a residence adorned with Art Nouveau details, merely within the confines of the “National Architecture Movement”?

EFFECT OF CHORD PRELOADING AND BRACE INCLINATION ON AXIAL RESISTANCE OF FULL-WIDTH RHS X-JOINT

According to current representative design standards, the influence of brace angle on the axial resistance of rectangular hollow section (RHS) X-joints is assumed to be independent of the chord preloading state. To investigate the appropriateness of this assumption, extensive test-validated finite element (FE) analyses are performed on full-width RHS X-joints with varying brace angles and chord preloads. The analyses showed that an appreciable coupling effect between the brace angle and chord preload exists on the joint resistances. The most adverse coupling effect occurs under the condition of high brace inclination and large compressive chord preload, leading to the concern that the current design resistance formula may overestimate the ultimate joint strength. Consequently, a revised chord stress function is sought for inclined full-width RHS X-joints that accounts for the coupling effect between chord preload and brace angle. In the FE analyses, high strength steel joints are included as well as conventional mild steel joints. The chord stress effect in high strength steel joints is found to be more detrimental compared to geometrically identical mild steel joints, implying that the chord stress effect may be influenced by the class (slenderness) of the chord cross-section. Therefore, a proper limitation on the chord section slenderness, such as the Class 2 requirement in design codes, appears essential.

Immediate effects of a buffered knee orthosis on gait in stroke patients with knee hyperextension.

Patients exhibit considerable variations in gait patterns especially in knee hyperextension in the stance phase after stroke. If knee hyperextension is untreated it may lead to pain, reduced independence in activities of daily living, deformities and instability. The aim of this study was to investigate the immediate effects of a buffered knee orthosis on gait of stroke patients with knee hyperextension. A total of nine patients with knee hyperextension after stroke were selected to wear buffered knee orthosis developed by Zhongshan Traditional Chinese Medicine Hospital and Ruike Medical Technology (Shanghai) Co., Ltd during walking training and daily walking. Then the gait analysis system of Motionanalysis was used to analyze and evaluate kinematic and spatiotemporal parameters of the gait in patients with independent walking or walking with a buffered knee orthosis. After wearing the buffered knee brace, initial contact, maximum and minimum angles of support phase, the toe off the ground, maximum and minimum angles of swing phase on the injured side of knee and ankle increased. Minimum angle of support phase and maximum angle of swing phase on the uninjured side of ankle decreased, while the toe off the ground and minimum angles of swing phase increased significantly (all P< 0.05); There was no significant difference in other kinematics, in parameters between time and space, in walking speed among subjective gait parameters (P> 0.05). Walking distance, confidence, sense of security, and the feeling of walking hyperextension were all improved. In addition, the number of asymmetric kinematic parameters and spatiotemporal parameters decreased. The buffered knee orthosis can effectively prevent knee hyperextension after stroke, improve the knee and ankle sagittal motion, gait asymmetry, gait subjective feeling, and does not affect gait space-time parameters.

Experimental and numerical investigations of block shear failure in gusset plates welded to double angle members

Double angle braces are used extensively in structures to resist lateral loads such as wind, earthquake, and blast loads. A possible failure mode in the gusset plate when all-around weld is used for the angles is the block shear failure. To date, only limited test data on welded gusset plates failing in this mode have been reported in the literature, and all of them only considered concentrically loaded gusset plates. This paper investigates the block shear failure in welded gusset plates experimentally and numerically when connected to double angle members with possible in-plane load eccentricity effects. The test results, including failure loads, fracture sequences, and load-displacement responses are reported in detail. Results showed that tensile fracture was initiated adjacent to the angle heel weld and then propagated along the tension plane. Due to existing in-plane load eccentricity, shear planes did not rupture simultaneously and the shear plane adjacent to the heel weld failed earlier. Following the testing, a numerical investigation using nonlinear finite element analyses with ductile damage capability was performed on the tested specimens. Subsequently, a parametric study was carried out to generate further numerical data over a wide range of gusset and angle dimensions, welding configurations, and connection lengths. Accordingly, the existing design equations for block shear strength as given by AISC specification were evaluated. It was shown that AISC provides excessively conservative and scattered failure loads because of ignoring stress triaxiality and using shear yield instead of shear rupture in its strength equations. In addition, equations specified for welded gusset plates by previous studies were considered and shown to be unsafe for general use. To address these shortcomings, an improved block shear strength equation is proposed in this paper and shown to predict the gusset strength in block shear with improved accuracy.

Stabilizing effect of an elbow orthosis with an adjustable hinge axis after lateral collateral ligament injury: A biomechanical study.

Current commercial elbow braces have a straight hinge that does not account for the native carrying angle of the elbow. The objective of this study was to determine the effectiveness of a custom-designed hinged elbow orthosis (HEO) with variable valgus angulations in stabilizing a lateral collateral ligament (LCL) deficient elbow. Eight cadaveric upper extremities were mounted in an elbow motion simulator in the abducted varus gravity-loaded position. The specimens were examined before and after simulated LCL injury and then with the addition of the custom-designed HEO with 0°, 10°, and 20° of valgus angulation. Kinematic data were recorded using an electromagnetic tracking system. The LCL injured state with or without the brace resulted in significant increases in varus angulation of the elbow compared to the intact state in both pronation and supination (P < 0.05). There were no significant differences in varus-valgus angulation or ulnohumeral rotation between any of the brace angles and the LCL injured state with the forearm pronated and supinated. The custom-designed HEO did not provide any additional stability to the LCL injured elbow. The varus arm position should be avoided during the rehabilitation of an LCL injured elbow even when an HEO is used.

An investigation of shear failure in welded channel and angle brace members

Shear yielding (SY) and shear rupture (SR) are base metal failure modes in welded connections of brace members to gusset plates. Although gusset plated connections have been extensively investigated in the past nonetheless, the shear failure limit states of welded brace members have not received significant attention. This paper aims to shed some light on the shear failure mechanism and strength of welded brace members consisting of single and double channels and angles. For this purpose, a nonlinear finite element (FE) model with ductile damage simulation is developed and validated against the authors’ experiments and other available test results. Then an extensive parametric study using 432 models is performed. The yield and ultimate failure loads of the members have been determined. The results show that the code-specified approach to predict the shear strength of members is very conservative and does not consider the existing tensile strength contribution of the members. In addition, the commonly assumed failure patterns are inaccurate. FE findings show that the SY limit state always occurs prior to SR with about 50% less strength. Moreover, it is found that the yielding mechanism in the SY limit state is limited to the connection region. The shear failure behavior under compression loading and the effects of connection geometry have also been examined. Based on extensive FE analyses, it is recommended to ignore the SY limit check in designing brace members. Moreover, a modification is proposed to the conventional SR formula using a block shear (BS) framework that includes tensile areas to predict the member’s strength more accurately. Application of the proposed recommendations in the seismic design of brace-to-gusset connections results in a more economical connection.

Maize varieties and their root trait variation mediate the development of rhizosphere arthropod diversity

While ecological roles of rhizosphere arthropods are well documented, little is known about the relationship between the development of plant roots and soil arthropod communities in agroecosystems. In this study, we investigated the effects of maize varieties and their root traits on the diversity and community composition of soil arthropods over time. Soil arthropods and root traits were evaluated before planting and at 30 and 60 days after planting in four maize varieties with different root growth angles and lateral root branching. Arthropod diversity declined from day 0 to 30 but recovered by day 60 with the development of maize roots. Two maize varieties (Nei 542018 and Nei 542022) exhibited lower brace and crown root angles, and arthropod taxon richness was greater in these two varieties than in others. The highest abundance of detritivores and predators was found in one of the maize varieties (Nei 542018) which, in addition to lower root angle, attained greater root diameter and lateral root branching and length. Redundancy analysis indicated that soil arthropod composition was correlated with crown root angle. Our findings highlight the importance of root traits, especially the angle of the roots, to enhance arthropod biodiversity in the rhizosphere ecosystem.

Designing Hierarchical IsoTruss Column Based on Controlling Multi-Buckling Behaviors

To develop large-span but ultralight lattice truss columns, a hierarchical IsoTruss column (HITC) was proposed. The multi-buckling behavior of the axially compressed HITC was analyzed by the finite element method (FEM) using a parametric approach in the framework of ANSYS parametric design language (APDL). It was demonstrated that the program enables efficient generation of the finite element (FE) model, while facilitating the parametric design of the HITC. Using this program, the effects of helical angles and brace angles on the buckling behavior of the HITC were investigated. Depending on the helical angles and brace angles, the HITCs mainly have three buckling modes: the global buckling, the first-order local buckling and the second-order local buckling. Theoretical multi-buckling models were established to predict the critical buckling loads. Buckling failure maps based on the theoretical analyses were also developed, which can be useful in preliminary design of such structures.

Influence of Factors on Effective Area of Bolted Steel Angles Under Tension

When the angle member is applied as a brace member, the eccentricity is inevitable at the joint, and a pair of bending moments act around both principal axes of the braces. Therefore, the effective net area is applied to design the angle brace members. The effective net area is assumed that part of the protruding angle leg is ineffective. According to Recommendations for Design of Connections in Steel Structures published by AIJ [1], the ineffective area is determined by the number of bolts (See Table.1). However, many researchers have investigated the angle members whose thickness is more than 6mm, and experimental data regarding the shape of the angle member is not sufficient. Therefore, the purpose of this study is to clarify the effects of parameters except for the number of bolts on the resistance and to establish an evaluation method of the angle brace member.

Conventional I-shape brace member bolted connections under seismic loading: Laboratory study

In many regions of the world, a conventional low-ductility concentrically braced frame (CBF) is commonly chosen as the seismic force resisting system. The energy dissipation is not restricted to yielding and buckling of the braces, as would be required for ductile braced frames; rather, energy dissipation is assumed to occur through localised yielding and friction in connections, as well as limited member yielding. The objective of this study was to characterize by means of laboratory testing the inelastic response of full-scale conventional I-shape braces and their bolted connections under reversed-cyclic seismic loading. Six brace specimens comprising two commonly used bolted connection types, flange plate and flange angle, were designed following the Type CC provisions prescribed by CSA S16. The brace specimens achieved storey drift ratios of 1%–2%, due to inelastic deformations in both the braces and the connections, even though capacity based design provisions were not incorporated in their design. Energy dissipation resulted from overall and local brace buckling, gusset plate buckling, tension yielding of flange plates, angles and gusset plates, block shear failure of brace webs and angles, bolt fracture and fracture of the gusset plates, along with bolt slip. However, the observed performance of these braces and connections in this laboratory based study is not necessarily guaranteed to be replicated for all conventional CBF designs due to the conservative nature and variability in accuracy of the existing CSA S16 design equations that were relied upon to design and detail the test specimens.

A seismic design method for one-piece gusset plate connections

In multi-story Special Concentrically Braced Frames (SCBFs), there are bracing nodes where two braces associated with two sequential adjacent stories of a similar bay intersect each other at beam-to-column joints. In these bracing nodes, under loading, one of the braces is in tension and the other is in compression. Consequently, maximum vertical force is imposed on the column. Note that in these bracing nodes, force distribution at a gusset plate affects the force distribution at the other gusset plate. Generally, two separate gusset plates are considered for the bracing nodes with two braces at the beam-to-column joints and designed according to Uniform Force Method (UFM). While the UFM proposed for corner gusset plates with one brace does not consider the force distribution effects at both gusset plates. To resolve this problem, the current study proposes a one-piece gusset plate for the bracing nodes with two braces at the beam-to-column joints. The one-piece gusset plate involves the gusset plate of the tension brace, the gusset plate of the compression brace, a part of the beam web whose length is equal to the interface of the gusset plate to the beam, and finger stiffeners. The finger stiffeners are considered in the connection region on both sides of the one-piece gusset plate to simulate the presence of the beam flanges removed in this region. Note that in this connection, the beam is extended to near the one-piece gusset plate and thereafter is connected to it. The aims of this study are as follows: (1) considering the force distribution effects on both gusset plates, (2) calculating the force and bending moment demands of the gusset plates in the bracing nodes with two braces at the beam-to-column joints via proposing a new method, and (3) determining the gusset plate dimensions in the bracing nodes with two braces at the beam-to-column joints through presenting a new procedure. Five one-bay, two-story SCBFs with the brace angles of 37−37, 45−45, 59−59, 37−59 and 59−37° (the first number is the lower story brace angle and the second number is the upper story brace angle) were designed in accordance with the method and procedure proposed in this study. These specimens were simulated in ABAQUS and subjected to a monotonic loading. The accuracy of the proposed method was confirmed via comparing the results of ABAQUS and UFM with those of the proposed method.

RESEARCH ON THE INFLUENCE OF GUSSET PLATE CONNECTIONS ON THE OUT-OF-PLANE STABILITY OF THE H-SHAPED STEEL BRACE

Experiments on 12 specimens of H-shaped steel bracing members with gusset plate connections (brace system) are conducted to study the effect of gusset plate on the out-of-plane rotational restraint and stability capacity of the brace. The experiments are under cyclic loading with constant-amplitude axial displacement, and the effect of clearance distance on the stability capacity of the brace is obtained. For the cyclic constant-amplitude loading condition, the degradation criterion of stability capacity of the brace system is obtained and the calculation formula of the post-buckling capacity is suggested. The finite element method is used to simulate the behaviors of specimens, and the simulated results are in good agreement with the experimental results. Moreover, a large-scale parameter analysis of the full-sized brace system is carried out. The results indicate that the brace slenderness ratio, the thickness of the gusset plate, the clearance distance and the brace angle have significant impacts on the out-of-plane rotational stiffness and stability capacity of the brace system. Based on the influence of these critical parameters on the rotational restraint of gusset plate and considering the size effect, the formulas for calculating the rotational stiffness of the gusset plate connection and the effective length factor of the brace are proposed, which can be used to easily obtain the stability capacity of the brace system.

Design of chord sidewall failure in RHS joints using steel grades up to S960

It is well known that the current design rules adopted by international design codes such as ISO 14346 and design guides, e.g., the CIDECT design guide No. 3, for chord sidewall failure in mild steel rectangular hollow section (RHS) joints under brace axial compression are considerably conservative, if the RHS joints are adequately supported out-of-plane. This paper presents an investigation into chord sidewall failure in RHS joints using steel grades up to S960. Representative existing design methods for chord sidewall failure in RHS joints are reviewed, and two alternative design methods, i.e., the modified bearing–buckling method and the Lan–Kuhn​ method, are proposed. Up-to-date test and numerical results reported in the literature are compiled. A wide range of geometric parameters, steel grades up to S960 and loading cases of brace axial loading, brace in-plane bending and brace out-of-plane bending are covered. The existing and proposed design methods are assessed against the collated results. The effects of brace-to-chord height ratio, brace angle, steel grade and chord stress ratio are evaluated. It is shown that the proposed design methods can provide more consistent resistance predictions for chord sidewall failure in mild steel and high-strength steel RHS joints under brace axial compression. Corresponding user-friendly design rules are suggested. The design of chord sidewall failure in RHS joints under brace axial tension, brace in-plane bending and brace out-of-plane bending is discussed. Further required research on, in particular, high-strength steel RHS joints is highlighted.

Super elastic system using parallel spine frames with steel braces

AbstractTo reduce the seismic response and residual deformation of structures, this study proposes a super elastic bracing system comprising parallel spine frames with steel rods acting as the braces connecting adjacent spine frames. The brace‐end connections are located on the outer side of the pin supports of spine frames to ensure that the axial deformation of the braces is lower than that of a regular bracing system with identical brace angles. To verify the feasibility and elastic range of the proposed system, cyclic loading tests were conducted using scaled specimens consisting of two spine frames with four different brace configurations. Numerical models created in OpenSees were used to simulate the loading tests appropriately. Four evaluation methods were developed for predicting the force and deformation relation considering the geometrical nonlinearity of the proposed system. Through parametric analyses, the influence of key parameters on structural behaviors is clarified, and the applicability of the evaluation methods is investigated.

Screening of Popcorn Genotypes for Drought Tolerance Using Canonical Correlations

Getting around the damage caused by drought is a worldwide challenge, particularly in Brazil, given that economy is based on agricultural activities, including popcorn growing. The purpose of this study was to evaluate popcorn inbred lines under water stressed (WS) and well-watered (WW) conditions regarding agronomic attributes, root morphology, and leaf “greenness” index (SPAD index), besides investigating the viability of indirect selection by canonical correlations (CC) of grain yield (GY) and popping expansion (PE). Seven agronomic, six morphological root traits were evaluated and SPAD index at five different dates during grain filling. The WS (−29% less water than WW) affected significantly the GY (−55%), PE (−28%), increased the brace and crown root density, and more vertically oriented the brace and crown angles. Higher SPAD index is associated with a higher yield, and these measures were the only ones with no significant genotype × water condition interaction, which may render concomitant selection for WS and WW easier. For associating the corrections of the different traits, CC proved to have better potential than simple correlations. Thus, the evaluation of SPAD index at 29 days after the anthesis showed the best CC, and based on the previous results of SPAD index, may be used regardless of the water condition.

Effects of far-field and near-fault cyclic loadings on seismic performance of naturally buckling braces in pairs

Naturally buckling braces (NBBs) have been previously developed through combining low-yield and high-strength steel channel segments with an intended eccentricity along the brace length. The developed NBB formed a novel mechanism and was experimentally verified to provide a ductile and stable seismic performance with the features of early yielding, large post-yield stiffness in tension and well-postponed local buckling in compression compared to conventional buckling braces. In this study, a series of paired NBB specimens have been tested to clarify the seismic performance of NBBs in pairs in frame systems, such as the effects of brace angles, member and local slenderness, and adopted steel grades of the low-yield segment. Two types of cyclic loading protocols, including far-field and near-fault cyclic loadings, were applied to investigate near-fault effects on the seismic performance of the paired NBBs compared to that under far-field cyclic loading. The test results verified that the paired NBBs provided a comparable, ductile, and stable hysteretic performance in tension and compression under both far-field and near-fault loading protocols. A procedure to transfer the nonlinear measured strength backbone curves to bi-linear strength curves was proposed to present the major hysteretic properties of the paired NBBs, and several general equations were established to accurately estimate the major hysteretic properties. Strength degradation was observed among the specimens and was more significant under near-fault loading. An equation was developed to accurately quantify the strength degradation according to the member and local slenderness ratios of the paired NBBs, and the relationship of the strength degradation between far-field and near-fault loadings was established. Cumulative plastic deformation and total energy dissipation of specimens in the study were evaluated to quantify the fatigue life of the paired NBBs. Finally, an improved modelling approach of the paired NBBs was suggested and experimentally validated to more accurately represent the seismic performance of the paired NBBs in the frames.

Numerical Study: Effect of Various Link Length to Lateral Force in Eccentrically Braced Frame

Eccentrically Braced Frame (EBF) is an excellent steel frame system for resisting earthquake forces. This frame shows good performance in terms of stiffness and has excellent ductility. When it is subject to a severe seismic event, the links undergo inelastic deformations and become the primary source of energy dissipation. However, the performance of EBF is strongly influenced by the length of the links that are an essential part of the EBF system. Links should be limited not be too short or too long because it relates to the stiffness and ductility of the frame. The study of EBF on the 80-90s also limits the ratio both of e/L not exceed 0.5 and the diagonal brace angle between 40°- 60°. This research will review the influence of the length of the links varied from the e/L ratio of 0.005 to 0.38. This variation will divide the links into three types of yielding, i.e., the short link, intermediate link with shear dominance, and intermediate link with bending dominance. In this study, the behavior of various link lengths on Eccentrically Braced Frame will be evaluated using finite element analysis using MSC Patran and Nastran. The structure is modeled as a one-dimensional D-Braced EBF type that is given static monotonic load with displacement control. The results obtained in the form of load-displacement curves which will be analyzed in strength and ductility. In addition, an ultimate load normalization curve will be generated to obtain the load pattern for the various link length. The curve shows that the ultimate load on the EBF will decrease if there is an increase in link length. The significant decrease occurs when e/L &gt; 0.2.

Numerical Simulation and Analysis of Thermal Stress on Restressed Assembly Steel Struts System in Foundation Excavation

When using horizontal internal bracing system in large span deep foundation pit, the influence of temperature effect on bracing system must be considered. Based on the long-term thermal stress monitoring of a project in the west of Hangzhou, this paper studied the influence of Angle brace temperature effect on the foundation pit enclosure structure after excavation to the bottom by using three-dimensional finite element model. When the strut temperature rises, the strut axial force increases. The longer the length is, the higher the axial force rises. The horizontal displacement of the surrounding wall and soil will be in the external direction of the pit, which is conducive to the stability of the surrounding system. The second layer struts are more affected by the temperature effect than the first layer struts, and the combined action of the two struts makes the surrounding wall produce greater displacement. The pouring of the bottom plate makes the strut subject to the temperature effect to generate greater axial force, the second layer struts change more violently, and at the same time reduces the displacement and deformation of the retaining structure. When the temperature drops, the strut axial force decreases and the horizontal displacement of the retaining structure to the pit increases, which is not conducive to the stability of the system. At this time, the reinforcement of the nearby soil body can be considered to reduce the deformation of the soil body and the retaining wall.