Analysis Of Frame Structures Research Articles

Dynamic Response Analysis of Open Section Structures with Warping Restraint Conditions and Impact Load Durations

The response analysis of frame structure with open section beams considering warping conditions and short duration load have been performed. When a beam of frame structure is subjected under torsional moment, the cross section will deform a warping as well as twist. For some thin-walled sections warping will be large, and accompanying warping restraint will induce axial and shear stresses and reduce the twist of beam which stiffens the beam in torsion. Because of impact or blast loads, the wave propagation effects become increasingly important as load duration decreases. This paper presents that a warping restraint in finite element model effects the behavior of beam deformation, dynamic mode shape and response analysis. The computer modelling of frame is discussed in linear beam element model and linear thin shell element model, also presents a correlation between computer predicted and actual experimental results for static deflection, natural frequencies and mode shapes of frame. A method to estimate the number of normal modes that are important is discussed.

Parameterized fragility analysis of steel frame structure subjected to blast loads using Bayesian logistic regression method

Civil structures might be subjected to blast loads during their lifetime. Since explosion is a low probability high consequence event, the damage assessment of structural system against blast loads needs a probability evaluation approach. This study presented a reliability analysis of steel frame structure against blast loads using Bayesian logistic regression method. Fragility functions parameterized on material properties and blast wave characteristics are developed and further utilized to assess the collapse risk of the structure. The imbalanced data set used in developing logistic regression model and the prediction uncertainty due to the limited data size are particularly stressed. The imbalanced data set is treated by generating synthetic data points for samples that are most likely to be misclassified. The prediction uncertainty is considered by constructing confidence intervals based on the posterior samples generated from Markov Chain Monte Carlo simulations. The developed risk assessment approach is applied to a 10-story steel frame as a numerical example. The probability of structural collapse is obtained and compared with the results from subset simulation method in conjunction with finite element analysis. Results show that the developed parameterized fragility function is accurate in predicting the probability of structural collapse against blast loads compared with the FE-based reliability method. The closed-form fragility function can be implemented to study the effect of parameter variations on the safety of the structure without additional FE simulations.

Time History Analysis of Frame Structure Systems by State-space Representation Method

This paper develops the state-space representation (SSR) in the field of seismic analysis of the building structures. Dynamic analysis of multi-degree-of-freedom structures involves the solution of second-order linear differential equations which they represent the equation of motion of the structure. In this paper, a SSR was formulated to replace differential equation with two coupled first-order linear differential equations. The objectives of this study are as follows: (i) To implement the SSR as a powerful tool in dynamic analysis of frame structures and (ii) to conduct a linear time history analysis for large structures subjected to ground acceleration and the seismic responses of the building were studied as well. The analysis was based on the assumption that the system is elastic linear time-invariant system and material nonlinearity is not considered. The 1940 El-Centro earthquake time history record has been used in the study. There are many effective traditional methods which can be used for carrying out linear dynamic analysis of the structures, however, this paper introduces a state-space model as an alternative approach to perform this analysis. The advantage of this method, it works properly with MATLAB software, gives explicit result for time-invariant systems, applied to multi-input and multi-output control systems, solve the equation of motion for complicated dynamic problems.

Carbon emission energy management analysis of LCA-Based fabricated building construction

With the gradual warming of the global climate, the development of low-carbon buildings has become an inevitable trend, and research on the carbon emissions of buildings is also imperative. At present, in most studies on energy management of carbon emissions during the construction process, people cannot analyze them with a more accurate method. In order to find an effective carbon emission analysis method, based on the life cycle assessment method (LCA), this paper establishes a carbon emission model, and calculates the carbon emission of residential building materials in different areas, building materials in different industrial buildings, air conditioning cooling and heating schemes, and the whole life cycle of buildings. This article draws the following conclusions: The relationship between the carbon emissions of residential building materials in different regions is: severe cold area>cold area>hot summer and cold winter area>mild area>hot summer and warm winter area. In the analysis of frame structure, brick concrete structure and steel concrete structure, the most carbon emission is steel concrete structure, and the least is frame structure. The carbon emissions of different forms of air-conditioning cold sources are different. Among them, the second option is the direct-fired lithium bromide absorption chiller and hot water unit. The carbon emissions are related to the energy structure. For prefabricated buildings, the proportion of carbon emissions in the construction use phase is the highest, reaching 75%–80%, and the sum of the construction use phase and the building material production phase accounts for more than 90% of the total.

Rational nonlinear analysis of framed structures and curved beams considering joint equilibrium in deformed state

Based on the continuum mechanics principles, a rigorous formulation is presented for the linearized stiffness equation of three-dimensional beam elements with account taken of the joint moment equilibrium in the deformed configuration C2. By sticking to the Bernoulli–Euler hypothesis of plane sections and elasticity definitions for stress resultants, the bending moments and torque of the element are shown to be quasi- and semi-tangential, respectively, in the updated Lagrangian formulation. Further, by invoking the moment equilibrium conditions for structural nodes at C2, the induced moment matrix that first appears to be antisymmetric on the element level turns out to be symmetric upon assembly of all elements on the structural level. The joint equilibrium conditions at C2, as represented by the induced moment matrix, are central not only to the out-of-plane buckling analysis of angled frames, but also to the simulation of curved beams by the straight-beam elements. Examples on the buckling of angled frames and curved beams are provided to support the theory presented.

Time domain intrusive probabilistic seismic risk analysis of nonlinear shear frame structure

Presented is a time domain intrusive framework for probabilistic seismic risk analysis. Seismic source characterization is mathematically formulated. Methodology for simulating non-stationary seismic motions for given source, path and site is proposed. Both uncertain motions and uncertain structural parameters are characterized as random process/field and represented with Hermite polynomial chaos. Intrusive modeling of Armstrong-Fredrick kinematic hardening based on Hermite polynomial chaos is formulated and incorporated into Galerkin stochastic elastic-plastic FEM. Time-evolving probabilistic structural response is solved through developed stochastic elastic-plastic FEM. Following that, formulation for seismic risk analysis is derived. The framework is illustrated by seismic risk analysis of an eight-story shear frame structure. Uncertainties are propagated from earthquake source into uncertain structural system. Difficulties of choosing intensity measure in the conventional framework are avoided since all the uncertainties and important characteristics (e.g., spectrum acceleration Sa and peak ground acceleration PGA) of seismic motions are directly carried by the random process excitations in time domain. Stochastic dynamic equations are solved in an intrusive way, circumventing non-intrusive Monte Carlo simulations.

Research on nonlinear, postbuckling and elasto-plastic analyses of framed structures and curved beams

Nonlinear analysis of structures is an effective way for predicting the bearing capacity or ultimate strength of a structure. This paper will review researches on the nonlinear, buckling, postbuckling and elasto-plastic analyses of three-dimensional (3D) framed structures. Also considered are curved beams since they share the problem of joint equilibrium in simulation. The following are the key issues to be covered in this paper: (a) analytical or semi-analytical approaches; (b) formulation for incremental-iterative nonlinear analysis; (c) joint equilibrium of 3D frames at the deformed configuration; (d) rigid body test for nonlinear finite elements; (e) rigid-body-qualified geometric stiffnesses and derivation; (f) simulation of buckling of curved beams; (g) elasto-plastic analysis of steel frames; (h) mechanism of iterations in incremental analysis; (i) recovery of element forces; and (j) path-tracing scheme for the postbuckling response. In this paper, the theories and methods for solving the postbuckling responses of structures involving multi-loop curves are considered. In fact, the incremental-iterative procedure for the geometric and/or inelastic nonlinear analysis can be greatly simplified if it is well rooted in physics. Namely, if the rigid body rule is fully obeyed at each stage of analysis, then the entire incremental-iterative procedure can be made simpler and more efficient. Recently, it was demonstrated that satisfactory results can be obtained for the postbuckling response of a number of structures using the elastic stiffness alone. A total of 154 references are cited in this paper.

Plastic Effect Analysis of High Strength Steel Frame Structure

High strength steel structure is more and more widely used in the field of building structure because of its advantages in mechanical properties. The design of high-strength steel frame often refers to steel structure. For the high-strength steel with no yield platform of stress-strain curve, the influence of plastic strain before the nominal yield strength of its material on the results of the frame remains to be studied. In order to study the influence of plastic effect on high-strength steel frame, the second-order elastic-plastic analysis of typical frame is carried out and compared with the simplified design method of steel structure design standard. The results show that the plastic effect has no significant effect on the bending moment and lateral displacement of high-strength steel frame in most cases. Base on the analysis results, the design suggestions of high-strength steel frame structure are put forward.

Enhanced model including moment-rotation dependency for stability of thin-walled structures

Adopting an updated Lagrangian approach, a “general” and “exact” framework for the geometrically non-linear analysis of thin-walled framed structures are developed. The generality of such framework stands for the wide range of its applicability for different types of beam cross-sections, support conditions, and loading patterns including configuration-dependent behavior of applied moments; while the exactness stands for the utilization of a number of closed-form solutions of a class of torsionally loaded thin-walled beams to formulate a two-node element for spatial buckling analysis. The key in this formulation relates to the use of the “exact” solution for the displacement fields as opposed to the more conventional finite element approach in which polynomial/Lagrangian-type interpolation function is employed. Further, emphasizes are given to the effect of finite rotations in space on the non-linear kinematic descriptions as well as the configuration-dependent behavior of externally applied moment vector of the conservative/non-conservative type. Results obtained in a number of numerical simulations of beam assemblages subjected to different loading patterns illustrated the usefulness, robustness and fast convergence of the developed model in predicting the lateral torsional buckling.

Structural steel design using second-order inelastic analysis with strain limits

Steel framed structures are affected, to greater or lesser extent, by (i) geometrical nonlinearity associated with the change in geometry of the structure under load and (ii) material nonlinearity related to the onset and spread of plasticity. In traditional design approaches, the design forces and moments within structural members are usually determined from simplified structural analyses (e.g. first or second-order elastic analysis), after which member design checks are performed to assess the strength and stability of the individual members. The extent to which the strength and deformation capacity of cross-sections is affected by local buckling is typically assessed through the concept of cross-section classification. For example, only compact (Class 1) cross-sections are considered to possess sufficient rotation capacity for plastic hinges to develop and for inelastic analysis methods to be used. This approach results in step-wise capacity predictions and is considered to be overly simplistic. Since the structural analysis of steel framed structures is typically performed using beam finite elements, which are unable to explicitly capture local buckling, a more sophisticated treatment of the available deformation capacity is required if inelastic analysis methods are to be used for all cross-section classes. A novel method of design by advanced inelastic analysis has recently been developed (Gardner et al., 2019a; Fieber et al., 2019a, 2018a, 2018b [1–4]), in which strain limits are employed to represent the effects of local buckling in beam finite element models and thereby control the spread of plasticity and level of force/moment redistribution within a structure. It is thus possible to use a consistent advanced analysis framework to design structures composed of cross-sections of any class. In the present paper, application of the proposed design method to continuous beams and planar frames is illustrated and assessed. Ultimate load capacity predictions are compared against results obtained from benchmark shell finite element models that explicitly capture local buckling and to conventional steel design. It is found that the proposed method predicts safe-sided ultimate capacities that are consistently more accurate than current design methods, particularly for structures benefiting from strain hardening and for structures composed of non-compact cross-sections where inelastic redistribution is typically ignored.

Optimization of a cantilever steel frame structure of bottom platform by finite element method

The finite element analysis of a cantilever steel frame structure of the bottom platform in civil engineering is carried out. Based on ANSYS and the basic characteristics of steel frame structure, parametric modelling is carried out, and the stress and deformation of the structure under extreme load conditions are analysed. The first-order optimization algorithm is used to optimize the beam cross-section size, which significantly reduces the total weight of the structure, thus providing a basis for the optimal design of the engineering structure.

Seismic Response Analysis and Control of Frame Structures with Soft First Storey under Near‐Fault Ground Motions

This paper proposes two kinds of arrangements of buckling‐restrained brace dampers to strengthen soft‐first‐storey structures locally. Two types of near‐fault ground motion, with and without pulse, were selected for a study of the seismic response characteristics of soft‐first‐storey structures with and without buckling‐restrained brace dampers, and the effects of different bracing arrangements on improving the seismic performance of soft‐first‐storey structures were recognized. The results show that, compared with pulse‐free ground motion, near‐fault pulsed ground motion results in a more severe seismic response in soft‐first‐storey frame structures, leading to more serious and rapid destruction of the main structure. Buckling‐restrained brace dampers have an obvious energy dissipation effect, play a better role in protecting the main structure, and have good practicality. Compared with structures in which the buckling‐restrained brace dampers are arranged only on the bottommost layer, the bottom‐four‐layer‐support structure is more advantageous in terms of seismic performance.

Modelling failure analysis of RC frame structures with masonry infills under sudden column losses

Robustness of structures is fundamental to limit progressive collapse of buildings in case of accidental loss of columns due to explosions, impacts or materials deterioration. Modelling of progressive collapse response of reinforced concrete (RC) frame structures needs considering extreme geometric and mechanical nonlinearities. Moreover, in the case of infilled frames the collapse mechanism becomes more complex because of the frame-infill interaction. This paper presents a numerical study aimed at proposing: a) an appropriate fiber-section modeling methodology for reinforced concrete frames under large displacement progressive collapse events; b) a new multi-strut fiber macro-element model to account for the influence of masonry infills in the progressive collapse response. Proposed numerical models are developed using the OpenSees software platform. The predictive capacity of the proposed methodology is widely validated in the paper through comparisons with experimental test results and refined numerical simulation pushdown test results. Results show that the new equivalent-strut modeling approach can be suitably employed as a simple assessment method when numerical simulation of progressive collapse scenarios is needed for bare and infilled reinforced concrete frames.

Comparative Analysis of Steel and RCC Frame Structure of a Commercial Building

Comparative Analysis of Steel and RCC Frame Structure of a Commercial Building

Journal of Scientific Temper

Coronavirus prevention efforts both protect the people who engage in them and promote the welfare of society. However, often not facts and information, but emotions drive the risk perceptions. Emotions influence our reasoning and impact on our behaviours. To tide over the COVID 19 epidemic, all people must abide by certain practices, ranging from easy to observe, but annoying, hand washing to more socially disruptive physical distancing. Lockdowns, curfews and other political and administrative measures make additional demands. Using frame and narrative structure analysis, in this paper, we examine two videos, prepared by the Kerala and Tamil Nadu police personnel for social media dissemination. Using the frame analysis methodology and narrative structure analysis, we explore the frames, stereotypes, metaphors, actors, and messages encoded in the selected two videos and draw inferences on the influence it can have on the audiences.

Static Analysis of Frame Structure of Post-Stroke Tricycle Design Based on Solidworks Software 2012 with Material Type Variations

The body weight of post-stroke patients varies from one another, this can affect material selection. In this study, the researchers designed a three-wheeled frame using various types of material and the same material size including: galvanized pipe, stainless pipe (AISI 304), mild steel pipe (ASTM A36), Alloy Steel pipe to obtain a safe design for sufferers post-stroke, the skeletal design was analyzed statically using Soliworks 2012 software to obtain the results of analysis in the form of: Von Mises Voltage, Safety Factor (Strain) and Strain (Displacement). Static analysis of Post-Stroke Tricycle Design results obtained the greatest Von Mises Voltage value on ASTM A36 type material with a stress value of 154.5 N/mm2 (MPa) and the smallest stress value in Galvanized type material with a stress value of 150.8 N/mm2 ( MPa). Based on the results of the analysis of Safety Factors (Safety of Factor) so that the design can be said to be safe for patients after stroke, the type of material that must be used is Alloy Steel with a value of Safety Factor (Safety of Factor) of 5.49.

Fragility Analysis of Concrete-Filled Steel Tubular Frame Structures with BRBs under Multiple Earthquakes Considering Strain Rate Effects

The fragility of concrete-filled steel tubular (CFST) frame structures with buckling-restrained braces (BRBs) subjected to multiple earthquakes is studied in this paper. First, a fiber beam element model with rate-dependent concrete and steel material properties is developed for CFST members and, then, the effect of the strain rate on the seismic response of the CFST frame structure is investigated numerically. The influence of BRBs on the seismic response of the CFST frame structure is then comparatively analyzed. The seismic responses of the CFST frame structure with BRBs under single mainshocks and earthquake sequences are investigated, and the fragility curves are generated using probabilistic seismic demand analysis. The obtained roof displacement and inter-story drift ratio (ISDR) of the structure decreased by 10.2% and 6.9%, respectively, when obtained while considering the strain rate effect, compared with those obtained without consideration of the strain rate effect. BRBs can effectively improve the seismic performance of the CFST frame structure in that the maximum roof displacement and ISDR can be reduced by 45.1% and 43.9%, respectively. Compared with those under single mainshocks, the maximum roof displacement and ISDR of the structure with BRBs under earthquake sequences significantly increase. The fragility of the BRB structure under earthquake sequences is more severe than that under single mainshocks. Therefore, the influences of the strain rate effect and earthquake sequence should be considered to realistically evaluate the seismic fragility of CFST structures.

Equivalent Frame Model with a Decaying Nonlinear Moment-Curvature of Steel-Reinforced Concrete Joints

A numerical model for the analysis of frame structures that is capable of reproducing the behavior of reinforced concrete (RC) members and steel-reinforced concrete (SRC) members in all steps until collapse by simulating a reduced resistance capacity is presented in this work. Taking into account the solid models obtained in previous research that have been validated by experimental results, moment-curvature graphics were obtained in all steps: elastic, plastic, and post-critical to collapse. Beam models versus 3D models considerably simplified the calculation of frame structures and correctly described both the plastic and post-critical phases. The moment-curvature graph can be used in a simplified frame analysis, from post critical behavior to collapse.

Frame structure analysis model of tunnel lining using nonlinear ground reaction curve

The new Austrian tunneling method (NATM) and the shield tunneling method can be applied to Diluvial and Neogene deposits, on which megacities are located in Japan. However, because the lining design techniques differ between the two tunneling methods, a unified concept for tunnel lining design is needed. To this end, in this study, a frame structure analysis model for tunnel lining design, developed based on the nonlinear ground reaction curve, is proposed. The proposed model can consider the passive and active earth pressure due to excavated surface displacement, including the effect of ground self-stabilization, and the excavated surface displacement before lining installation. In the evaluations of the model’s performance, the measured earth pressure acting on the lining at the site of a Diluvial deposit was compared with the earth pressures calculated by the proposed model and the conventional linear model. The results verify that the proposed model can reasonably represent the earth pressure acting on the lining, lining displacement, and lining sectional force for various ground types, ranging from soft ground to stiff ground.

Advanced flexibility-based beam-column element allowing for shear deformation and initial imperfection for direct analysis

In this paper, a new flexibility-based beam-column element allowing the interaction of shear deformation and initial imperfections is proposed. The element is based on Hellinger-Reissner functional with exact force interpolation functions. An extended displacement interpolation based on the curvature and shear strain is adopted to account for shear effects. The member initial imperfection is considered in the derivation of elemental formulation while the distributed plasticity is taken into account by fiber section approach. Three-dimensional inelastic materials are adopted to consider the coupling effect of axial force, bending moments and shear forces. A special element state determination method is adopted to incorporate the proposed element to the conventional finite element programs. The proposed work provides one-element per member model for practical direct analysis with consideration of shear deformation, initial imperfection and material yielding, which is limited in literature. Several numerical examples are demonstrated the accuracy and efficiency of the proposed element in second-order direct analysis of frame structures.