Steel Space Research Articles

Optimization of roofs with solar panels using Rao algorithms

Steel space truss roof (SSTR) systems are widely used in structures with large spans such as stadiums, sports halls, and shopping malls, as well as in industrial buildings such as factories, workshops, and production facilities. Solar panels are integrated into SSTR systems to enable these structures to generate energy and to increase the use of sustainable energy sources. With the installation of the solar panels, an additional load was placed on the roofs. However, this raises questions regarding whether existing roofs can withstand this additional weight without compromising their design. This study can be an important reference source for future truss roof designs by increasing sustainable energy use and functionally optimizing the SSTR. Another contribution of this study is that it directly contributes to real-world applications by ensuring that SSTR designs are more efficient and economical for engineering projects. For these purposes, this study presents the size optimization of the SSTR with and without solar panels using the Rao-1 and Rao-2 algorithms, which are metaheuristic algorithms known as the Rao algorithms. Thus, information can be provided regarding whether existing roofs can safely carry solar panels. To optimize the SSTR system, a computer code was created in MATLAB, which works effectively with Rao algorithms and SAP2000-s Open Applicable Programming Interface (OAPI) features and allows repetitive analysis. For size optimization of the SSTR, which consists of 1728 elements, the roof system was divided into three and six groups. Changes in the weight of the SSTR system in the different groups were investigated. The optimum design of both the three-group and six-group SSTR systems with and without solar panels was performed. Based on the results obtained from this study, it was concluded that the Rao-1 algorithm achieved more robust and stable results than the Rao-2 algorithm in both three and six-group SSTR. The SSTR system divided into six groups achieved the minimum weight compared with the SSTR system, which was divided into three groups. In this case, increasing the number of groups provided better results.

An optimal design approach for steel space frames with T-stub semi-rigid connections considering soil-structure interaction

An optimization technique for designing the steel space frame with T-stub semi-rigid connections and interaction between soil and structure is presented in this article. A three-parameter-based elastic foundation model is utilized to investigate soil-structure interactions (SSI). To enable two-way data transfer for all optimization methods, computer software was developed using C# version 17.8.6, which connects to SAP2000-OAPI version 22. Particle swarm optimization (PSO) and teaching-learning-based optimization (TLBO) are employed for optimal designs. These optimization techniques choose profile sections from a list, including 64W discrete sections from the American Institute of Steel Construction (AISC). The Load and Resistance Factor Design-American Institute of Steel Construction (LRFD-AISC) strength constraints, geometric constraints, inter-storey drift constraints, and displacement constraints are considered during optimization. The first phase entails creating optimal designs for two unique steel space frames that consider SSI but do not include T-stub semi-rigid connections. Following that, the same optimization procedures are carried out with T-stub semi-rigid connections. The parameters needed for the foundation model are obtained through soil surface displacements. Utilizing T-stub semi-rigid connections while considering the interaction between the structure and the soil produces increased structural weight.

Influence of Soil Structure Interaction on Seismic Performance of Steel Structure Interaction with Different Types of Foundations and Soil

Soil Structure Interaction is the reaction of soil that influence the motion of the structure. During serve seismic events, the dynamic response of the structure is affected not only by the behavior of the superstructure but also by the nature and behavior of the soil present in and around the substructure. The steel structure design process usually assumes the base of the foundation to be completely restrained in a fixed base condition. In the present project the influence of soil structure interaction on the seismic performance of a steel space frame on different soil has been investigated. The multi-story steel building (G+7) with column to column spacing distance 5m and six number of columns having both X and Y direction of the structure, is designed to withstand self-weight and seismic loads. The study also examined the impact of earthquake loading on the steel structure with soil structure interaction using Response Spectrum Method and Time History Method for seismic zone III, with forces determined using IS 1893 (Part-3):2015. The study measured the displacement of steel structure with influences of soil under seismic forces. Comparison of seismic performance like maximum storey displacement, maximum storey drift and base shear along with soil structure interaction under different types of soil are presented in this project. This paper discusses the influences of the soil structure interaction on steel structure with various configuration and different types of foundations and soil.

Numerical design optimization of real size complex steel space frame structures using a novel adaptive cuckoo search method

AbstractIn this study, real size complex steel space frame structures are numerically designed to achieve optimal design weight. For this aim, standard cuckoo search algorithm is rectified through a newly proposed adaptive method over two fundamental algorithmic parameters of alien egg probability detection (Pa) and step size control (α) to overcome incompetency of trapping into local optima. Besides, to strengthen exploitation phase of newly proposed algorithm, it is boosted with greedy selection (GS). So, novel algorithm has more promising exploration and exploitation capabilities. An 8‐story, 1024‐member and a 20‐story, 1860‐member real size complex steel space frame structures are selected as design examples. Also, initially to verify the supremacy of novel algorithm, a well‐known welded beam is optimized as a benchmark structural design problem. Afterwards, the steel space frame structures are optimally designed via novel algorithm. Since ready steel section lists are utilized as selection pool for design variables, discrete programming problem is come into existence. The dead, live, snow, and wind design loads acting on frame structures are calculated in direction of ASCE 7‐05 provisions. Furthermore, the structural design constraints are determined from LRFD‐AISC specifications. Eventually, the newly proposed adaptive cuckoo search algorithm boosted with GS presents outstanding algorithmic performance.

Investigating mechanical characteristics of novel precast segmental lining using experimental and numerical methods

In recent years, precast segmental lining (PSL) has attracted much attention in tunnel engineering. In practice, the segmentation method is an essential consideration for PSL. This study proposes a novel PSL with a specific steel space truss. It uses physical and numerical modeling and considers three different segmentation principles in the experiments. In addition, this research develops an accurate three-dimensional finite element model, enabling a detailed analysis of the novel PSL. It also investigates the influence of joint thickness and stiffener on the novel PSL. The experimental results indicated changes in the lining's displacement, internal force, and failure mode. They revealed that cracks initially appear at the block joints. Considering the force and deformation of the lining, the method based on the maximum moment position principle is optimal because it can achieve the lowest deformation and bending moments. The numerical results showed that increasing the joint thickness or welding stiffeners raises the bending stiffness, reduces the joint opening, and decreases the plastic zone and strain value, thereby improving the joints' reliability. The findings are advantageous for the tunnel PSL design and can serve as a reference for joint optimization.

Ginger Essential Oil Inhibits Biofilm Formation of Streptococcus mutans on Stainless Steel Placeholder

Streptococcus mutans (S. mutans) forms biofilm on dental apparatus and materials in the mouth as far as the tooth surface is concerned. This form of biofilm around the apparatus can cause decay in the teeth. In our study, the formation of biofilm on the stainless-steel space maintainer, which is frequently used in children, and its inhibition by ginger essential oil were examined. Minimum inhibitory concentration (MIC) assays for the antibacterial activities of the ginger essential oil was performed according to the microdilution broth method. The formation of the biofilm on the stainless steel space maintainer was evaluated spectrophotometrically and the number of bacteria in the biofilm was counted. Biofilm on stainless steel space maintainer was also examined with scanning electron microscopy (SEM). On the stainless steel space maintainer without ginger essential oil, S. mutans produced significant amounts of biofilm. Bacterial counts and SEM images also supported this finding. Ginger (Zingiber officinale) essential oil significantly inhibited the formation of biofilm and adhesion of S. mutans on the stainless-steel placeholder.

Optimum design of steel frames with sizing and orientation design variables using a reformulated evolution strategy

Sizing optimization of steel frame structures has been traditionally conducted based on fixed orientations of structural members. However, it seems more expedient to search for an optimum design where orientations of column members are considered as design variables together with sizing of all members for the minimum weight design of a steel frame. In order to solve the resulting optimization problem effectively, a reformulated evolution strategy (ES) algorithm is proposed and employed in the present study. The numerical investigations are carried out using three test problems regarding the optimum design of steel space frames. In each test problem, a frame is first designed for the minimum weight considering sizing design variables only, where initial orientations of the column members are kept unchanged. Next, sizing and orientation design variables are considered simultaneously for minimizing the weight of the same frame. The results obtained in the foregoing two cases are compared and the associated optimal layouts for the column orientations are depicted. The study reveals that the optimal selection of column orientations has a significant influence on the minimum weight design of steel frames.

Seismic Assessment and Retrofit of Pre-Northridge High Rise Steel Moment Resisting Frame Buildings with Bilinear Oil Dampers

This paper presents quantitative information on the effectiveness of seismic retrofit solutions using bilinear oil dampers for seismically deficient existing tall steel buildings. For this purpose, a benchmark 40-story steel space moment-resisting frame building is studied that represents 1970s design practice in North America. Rigorous seismic performance assessment based on ASCE 41 recommendations reveals a high collapse risk for the existing building. The local engineering demand parameters are comprehensively assessed to quantify the impact of seismic retrofit on steel columns and column splices, which are particularly vulnerable due to the time of construction. Multiple retrofit schemes are explored with numerous damping levels and vertical damping distribution methods. The dampers are designed via a recently developed multi-degree-of-freedom performance curves method. A new balanced vertical damping method is proposed to account for the effects of frame inelasticity. This strongly depends on the supplemental damping level, and it determines the effectiveness of the employed vertical damping distribution method. The results indicate that the proposed retrofit strategies can minimize the collapse risk of the tall building. It is shown that the balanced vertical damping distribution method provides the most uniform drift distribution along the building height. Despite the reduction in story drift ratios, the axial force demand in exterior columns remains relatively high in the bottom stories regardless of the seismic retrofit solution. On the other hand, bilinear oil dampers produce relative constant forces despite exhibiting higher velocity demands than expected.

Detection of damage in offshore jacket structure using artificial neural network

With industrial growth over the years, geologists have begun to search for offshore sources of oil and natural gas. Most offshore oil-production platforms are jacket type. Offshore jacket structures consist of welded steel space frame. Tubular pipes are opted as they reduce hydrodynamic loads making them highly durable structures. However due to natural phenomenon like cyclones, earthquakes, etc. these structures can get adversely damaged. Apart from that the structure also degrades due to corrosion and fatigue due to the severe conditions it is always exposed to. In many cases physical inspection of the structure for checking damages is not possible due to unfavourable onsite conditions or lack of trained professionals. Hence there is a need to develop alternatives solutions. In recent years much research has been done in the application of Artificial Neural Networks (ANN) in Civil Engineering. ANN are computation systems that are inspired by biological neural systems. This paper aims at creating an ANN to identify damage in an offshore jacket structure using the modal parameters. The training set for the ANN is obtained by using a finite element software. The ANN is then tested using a test set and then it will be used to predict the structural damage in an offshore jacket structure.

Reliability-based layout optimization of concentrically braced in 3D steel frames

For an economical and safe design of building systems with concentrically braced frames, the layout of the braces should be done by considering all limitations. The current study proposes an approach for a reliability-based optimal design of concentric bracing layouts in 3D steel frames. The objective function was considered to be a reduction in the total weight. The layout of the braces was considered as the variable of the optimization problem. The deterministic design constraints of limitations of strength, drift and torsional irregularities were considered according to AISC 360-16 and ASCE 7-16. The distance between the center of mass and the center of rigidity was defined as the probability constraint. The probabilistic variables were the intensity of the distributed loads and the cross-sectional area of the braces and columns. The reliability index was evaluated using the Monte Carlo simulation method. The reliability-based design optimization (RBDO) problem was solved for 4-, 5- and 9-story steel space frames using the EVPS algorithm. To investigate the effect of the probabilistic constraint on the optimal design, numerical examples were solved without applying this constraint and the solutions to the RBDO and deterministic design optimization problems were compared.

Seismic behavior of steel space truss connections to reinforced concrete supporting columns

Roof joint is a critical connection in space truss structures, which connects the upper steel space truss roofs and reinforced concrete structures. Because of its simple structural detailing and easy construction, a typical kind of roof joint is comprised of four embedded anchor rods, a mortar layer, a base plate, and stiffeners are popular in small- to medium-span space truss structures. Among them, base plates with slotted bolt holes are commonly used to release the deformation caused by temperature change or earthquake input. The roof joints were considered either as pinned or rigid connections in the design. In this paper, quasi-static tests investigating the influence of the applied axial force and the shape of bolt holes on the shear resistance and seismic behavior of roof joints were performed. The roof joints exhibited semi-rigid connection behavior and two types of initial resistance mechanisms, sliding and overturning, were observed. With the increase of applied axial force, the behavior of roof joint changes from sliding to overturning. Finally, effective methods to determine the initial resistance mechanism and calculate the ultimate shear strength of roof joints are proposed. These findings and analyses may provide guidelines for roof joint design practice for space truss structures.

Dynamic Behavior of a Suspended Steel Space Frame-Glass Composite Floor

This study investigates the dynamic performance of a large-span suspended steel space frame-glass composite floor (SSSF-GCF). Both the ambient vibration and the human-induced vibration of the floor were experimentally measured to identify vertical dynamic characteristics and evaluate vibration serviceability of the floor. Although vertical dynamic characteristics of the floor based on the global simplified finite element (FE) model of the structure agree well with those identified via experimental modal analysis, the global simplified FE model significantly underestimates vertical vibration amplitudes of the floor due to the coupled effect between two layers. Accordingly, an equivalent local FE model of the floor system was proposed and updated via adjusting the vertical stiffness of the interstory hanging pillars. It is shown that the equivalent local FE model can well predict both the dynamic characteristics and human-induced vibration response of the floor. Finally, the effect of the damping ratio on the acceleration response of the floor was numerically demonstrated with the verified local FE model.

Performance of Jaya algorithm in optimum design of cold-formed steel frames

This paper presents a research on optimum design of cold-formed steel space frames using a new algorithm method named Jaya, which has been developed in recent years. The most obvious difference of Jaya algorithm from other algorithms is that it does not need any control parameters for updating. However, Jaya algorithm is able to successfully reach the optimum solutions without any delay. In this study, in order to test the robustness and practicality of this novel algorithm technique, different steel space frame problems that have been studied with other algorithms in literature are examined. The minimum weight designs of the problems are carried out by selecting suitable C-section from a prepared list including 85 C-sections with lips taken from American Iron and Steel Institute (AISI 2008). A program is coded in MATLAB interacting with SAP2000 OAPI (Open Application Programming Interface) in order to obtain optimum solutions. The strength constraints according to AISI-LRFD (Load and Resistance Factor Design), lateral displacement constraints, inter-story drift constraints and geometrical constraints are taken into account in the analyses. Two different cold-formed steel space frames are taken from literature to research optimum solutions by using Jaya algorithm. The first steel space frame is 379-member and the second steel space frame is 1211-member. The results obtained using Jaya algorithm are compared with those in reference studies. The results prove that Jaya algorithm technique is quite successful and practical optimum design of cold-formed steel space frames.

Dual-purpose concrete domes: A strategy for the revival of thin concrete shell roofs

The use of thin concrete shells as long-span roofing solutions has declined over the past 60 years, largely as a result of the expensive nature of the formwork for curved surfaces, and the stiff competition from other more economical options such as steel space grids. The purpose of this contribution is to explore the simultaneous use of thin concrete shells for roofing and liquid-containment purposes. It is hoped the concept of dual-purpose concrete shells will provide enhanced justification for the higher costs associated with the construction of curved surfaces, thereby helping to revive the widespread use of elegant thin concrete shells once again. Specifically, the state of stress in various dual-purpose configurations is evaluated, and the effect of varying shell thickness in critical zones is investigated, allowing some preliminary insights to be gained. With appropriate thickness enhancement in the critical zones, the concept appears feasible, but before firm conclusions can be made, detailed buckling studies need to be undertaken.

Performance evaluation of artificial bee colony algorithm and its variants in the optimum design of steel skeletal structures

Artificial bee colony algorithm (ABC) has been efficiently used to obtain the optimum design of structures under design code limitations. There are several enhancements suggested to improve the performance of ABC even further in the literature. In this chapter, the performance of enhanced ABC variants in the optimum design of steel skeletal frames is studied. The mathematical model of such design problem when based on the provisions of design code requirements results in a discrete nonlinear programming problem. Seven variants of ABC is selected from the literature. These are standard artificial bee colony algorithm (sABC), artificial bee colony algorithm with orthogonal learning (OCABC), quick artificial bee colony algorithm (qABC), noel chaotic artificial bee colony algorithm (STOC-BC), directed artificial bee colony algorithm (dABC), improved artificial bee colony algorithm (NSABC) and artificial bee colony algorithm with Levy flight distribution (ABC_Levy). Seven optimum design algorithms are developed to obtain the solution of the design problem formulated considering design code provisions. Two steel space frames, one ten story and the other fifteen story are optimized using each of the seven optimum design techniques. The performance of each variant is observed and the optimum designs are compared. It is noticed after carrying out the statistical analysis that ABC_Levy and qABC algorithms outperform the other algorithms.

Member Sizing Optimization of Large Scale Steel Space Trusses Using a Symbiotic Organisms Search Algorithm

A systematic approach of optimization is needed to achieve an optimal design of large and complex truss structures. In the last three decades, several researchers have developed and applied various metaheuristic optimization methods to the design of truss structures. This paper investigates a new metaheuristic algorithm called symbiotic organisms search (SOS) for member sizing optimization of relatively large steel trusses. The case studies include a 120-bar dome truss and a 942-bar tower truss. The structural analyses are carried out using the standard finite element method. The profiles of the truss members are circular hollow structural sections selected from a set of the American Institute of Steel Construction standard profiles. The design results using the SOS are then compared to those obtained using other metaheuristic methods, namely the particle swarm optimization, differential evolution, and teaching-learning-based optimization. The comparison shows the superior performance of the SOS in terms of the optimal solution, consistency, and convergence. Thus, the SOS is a good alternative for optimizing the design of steel truss structures in real engineering practice.

Development of Bridges Maintenance Management System based on Geographic Information System Techniques (Case study: Al-Muthanna \ Iraq)

A Geographic Information System (GIS) is a computerized database management system for accumulating, storage, retrieval, analysis, and display spatial data. In general, GIS contains two broad categories of information, geo-referenced spatial data and attribute data. Geo-referenced spatial data define objects that have an orientation and relationship in two or three-dimensional space, while attribute data is qualitative data that can be counted for recording and analysis. The main aim of this research is to reveal the role of GIS technology in the enhancement of bridge maintenance management system components such as the output results, and make it more interpretable through dynamic colour coding and more sophisticated visualization techniques than the conventional tabular data format.
 To achieve the main objective of this research, two study areas have been chosen: the old constructionbridge (Al-Qadisiyah bridge) and the newly constructed bridge (Barboty bridge). Both of them are in Al-Muthanna city \ Iraq. The data collection process was achieved in two stages: the first stage is providing a georeferenced satellite image for each study area for the purpose of producing a two-dimensional map. The second stage includes the field surveying process by total station and level instruments.
 GIS have been used to create a comprehensive database (Geodatabase) for both study areas. Geostatistical analysis was carried out in which the settlement areas of both study areas were defined by producing a colour image. The statistical tables for these analyses showed that the highest decline in the elevation reached at Al-Qadisiyah bridge to 19 mm in the middle of the bridge which is coloured as a red areas. On the other hand, it was found that the highest decline in the elevation of the Barboty bridge is 16 mm in the last part of steel space which is also coloured as a red areas.

A research on optimum designs of steel frames including soil effects or semi rigid supports using Jaya algorithm

The effect of soil foundation plays active role in optimum design of steel space frames when included. However, its influence on design can be calculated after a long iterative procedure. So it requires longer computer time and more computational effort if it is done properly. The main purpose of this study is to investigate how these effects can be calculated in more practical way in a shorter time. The effects of semi-rigid column bases are taken into account in optimum design of steel space frames. This study is carried out by using JAYA algorithm which is a novel and practical method based on a single revision equation. The displacement, stress and geometric size constraints are considered in the optimum design. A computer program is coded in MATLAB to achieve corporation with SAP2000-OAPI (Open Application Programming Interface) for optimum solutions. Four different steel space frames including soil structure interaction taken from literature are investigated according to different semi-rigidly supported models depending on different rotational stiffness values. And the results obtained from analyses are compared with the results available in reference studies. The results of the study show that semi-rigidly supported systems in the range of appropriate rotational stiffness values offer practical solutions in a very short time. And close agreement is obtained with the studies on optimum design of steel space frames including soil effect underneath.

Effect of temperature stress on main structure in waste incineration power generation plant

Waste incineration power station includes many functional structures, such as garbage discharge, storage, sorting and feeding units, boiler unit, tail gas treatment unit, leachate treatment unit, and coal storage unit. The structural forms of each part are different. Because of the particularity of garbage, structure units are required to be as close as possible and temperature joints should not be set up for the sake of possible leakage of exhaust gas or effluent liquor, so various structural units are integrated, which leads to the difficulty in structure design, and thermal stress cannot be neglected. In order to understand the effect temperature stress on main plant structures, a finite element model is established to study the distribution of thermal stress of the whole structure under three conditions: heating in summer, cooling in winter and heating in winter. It is found the influence of temperature on frame beam, column and steel space truss can be neglected, and the thermal stress on floor cannot be neglected [1]. The maximum stress is mainly distributed on both edges of floor along the longitude direction of structure. For those regions where stress concentration occurs, reinforcement bands or reinforcement mesh can be used to reduce the tensile stress. The analysis results show that this measure is effective and provides a reference for the design of the main structure of waste incineration power plant. This paper innovatively analyses the structure system of main workshop of refuse incineration power plant, which is composed of steel structure and concrete structure, and describes the skills and key points of complex system modeling. According to different seasons and heating temperature difference, the temperature stress on the surface of the structure is analyzed, which provides a reference for calculating degree stress and temperature difference of the similar structure system. The weak part of resistance to temperature stress in the structure system composed of concrete structure and steel structure is found out, and the corresponding solutions are put forward, which provides guidance for the construction of the main workshop of refuse incineration power station.

Design of Tapered Flatted End Tube for Tension and Compression Loading

Hollow circular tube has the most efficient section in space structure. Hollow circular tube joint either welding or bolting but welding aluminum structural alloys lead to unavoidable annealing which can reduce efficiency to the order of only 50%. The efficiency of riveted and bolted joints is usually assumed to be around 75% in both aluminum and steel construction. Welded connections give the maximum strength in steel space structures and used for large spans. Hollow circular tube flatted at the end for single bolted connection and at flatted end increase this thickness for reducing stresses and this thicker plate make a hole for single bolted connection. Study this performance for varies the tapered flattened angle tube. Apply vertically upward and downward incremental load on the tapered flatted end tube at fixed bolted joint in ANSYS. Run this model for maximum shear stress and maximum principal stress. Find out the allowable tensile and compression stress in simple hollow circular tube in SAP2000 as per IS800-2007.. Find out the design load as per maximum shear stress theories and maximum principal stress theories