Gabled Frames Research Articles

EFFECTIVE OPTION OF REINFORCEMENT FOR REINFORCED CONCRETE TAPERED ELEMENTS

Despite a large number of experimental and theoretical studies on the resistance to shear and crack formation of tapered elements, there are no reliable data in the domestic and foreign literature on the distribution of stresses in such elements in areas near fractures of the faces.
 In the article, based on the results of experimental studies, an analysis of the stress-strain state of tapered elements is performed. The main design factors affecting the stress distribution, as well as the nature of the formation and development of cracks are revealed. It is established that in gable beams, inclined cracks are formed not only in the support zone, but also in the middle of the span directly at the ridge, even in the absence of transverse force. The features of the stress-strain state of the beams of the broken outline are associated with the occurrence of tangential stresses from the action of the bending moment and longitudinal force due to the variable height of the section of the element, as well as with the formation of local stress fields in areas near the fractures of the faces.
 Based on the data obtained on the basis of experimental and theoretical studies, an effective option for reinforcing ridge zones of reinforced concrete gable beams and frames is proposed.

31 Alternative Housing for Beef Cow/Calf Producers: A Survey of Management Practices and Health Concerns

Abstract The objective of this survey was to assess how building designs impact management practices and health concerns in confinement-housed beef cow-calf operations. This oral-based, on-farm survey collected responses from 20 cow-calf producers across the state of Illinois who were currently using an alternative housing system. The survey consisted of 94 questions based on 10 categories: demographics, housing, technology use, herd health and nutrition, pasture, manure management, cover crops, feed storage, water, and genetics. There were a variety of question types including multiple choice, select all that apply, open-ended, ranking of importance, and scale from one to ten. Results were analyzed based on respondents building design type (monoslope; n = 6, gable frame; n = 5, and hoop; n = 9). For the producers utilizing a monoslope, 66.7% had cow inventories of 150 or more, whereas 60% of gable frame users had inventories of 150 or more, and 44.4% of hoop building users had inventories of 150 cows or more. For the producers utilizing a monoslope, 16.7% had rubber covered concrete slat flooring, 33.3% had a clay/lime-based flooring, and 50% had concrete flooring. For the producers utilizing a gable frame, 0% had slats, 60% had lime, and 40% had concrete. For the producers utilizing a hoop building, 0% had slats, 88.9% had lime, and 11.1% had concrete. When assessing drylot access, 0% of monoslope users were allowing cows access to a drylot compared with 40% of gable frame users and 66.67% of hoop building users. Most monoslope users (83%) had 6 months or more of under-roof manure storage, whereas 0% of gable frame users did, and only 11.1% of hoops users did. For those utilizing a monoslope, 50% were creep feeding for 4 months or more compared with 80% of gable frame users and 12.5% of hoop building users. For producers utilizing a monoslope, 60% responded cows were over-conditioned, 40% said properly conditioned, and 0% said under-conditioned. For gable frame users, 50% responded cows were over-conditioned, 50% said properly conditioned, and 0% said under-conditioned. For hoop building users, 44.5% responded cows were over-conditioned, 55.5% said properly conditioned, and 0% said cows were under-conditioned. When asked to rank calf issues, 67% of monoslope producers ranked scours first, compared with 40% of gable frame users, and 44% of hoop building users. None of the monoslope users ranked calf respiratory first whereas 40% of those with gable frame did and 22% of hoop building users did. For naval issues, 33.3% of monoslope ranked it first, compared with 20% of gable frame users, and 33% of hoop building users. In conclusion, building design type influenced management practices and health issue concerns.

An enhanced meta-heuristic algorithm for optimizing the roof slope of tapered steel frames

Steel gable frames, or pitched roof portal frames, have been widely used for industrial building applications due to their ease of erection and fabrication. The roof slope is one of the most important geometric characteristics of gable frames. The roof slope affects wind loads, snow loads, rainwater drainage, and the optimal weight of the frame. The purpose of this study is to find the optimal roof slope of gable frames with tapered members for different spans. A novel meta-heuristic optimization algorithm called the Enhanced Crystal Structure Algorithm (ECryStAl) is utilized to optimize the steel frames. In this broad study, all practical load types, load combinations, and design constraints are considered for the structural optimization process. The results of this study show that up to 39.50% of the project material cost can be reduced by the proper choice of the roof slope depending on the span length and column height as the optimal roof slope depends mainly on them. In addition, mathematical models, which can be used in practical design situations, are developed to determine the optimal roof slope for different span lengths and column heights.

Optimal configuration of tapered steel gable frames based on total installed costs using the Enhanced Crystal Structure Algorithm

Steel gable frames are the structural system of choice for industrial buildings and warehouses. As the frame span length and column height increase, prismatic members become economically infeasible, whereas tapered members can be optimized to provide the highest material usage efficiency and the least possible cost. The objective of this study is to compare the optimal design of four different practical configurations of tapered steel gable frames against the case of using prismatic members. Therefore, the optimal configuration for each span length, column height, and loading condition can be determined. Five distinct loading conditions are considered including high wind loads, high seismic loads, and low, medium, and high snow loads. The study results led to developing decision support charts to determine the optimal configuration based on the ratio of the material cost to the total installed costs, including material, fabrication, and erection costs. In addition, higher material savings can be achieved by using tapered members with a larger number of member divisions and design variables by about 14% up to 25.3% compared to using only prismatic members.

The STUDY OF RESISTANT EARTHHQUAKE BUILDING OF TIMBER ROOFS STRUCTURE AND ITS RETROFIT AND REDESIGN AFTER THE SEPTEMBER 28 2018 EARTHQUAKE

Palu’s Earthquake on 28 September 2018 had caused structural failure including buildings with wooden structures which were knew as an earthquake-resistant structures. This study will discuss existing building timber roofs structure were damaged after the earthquake, various and caused of the damaged. Existing and retrofitted timber rooss and alternatives design of the roofs structures will be compared. Retroffited timber roof, truss roof with 70x70x6 double angle and gable frame roof structure with WF 250x125 will be design with 15 m length span and 45° slope. Based on these data collected from initial assessment of that buildings, analysis was conducted. Detailed assessments were carried out, when analysis of the truss, frame and joint of roofs structures were needed. Results of the initial assessment of wooden structure, showed that damages occurred at the many joints of member joints and joint-connection between wall and truss as the poor connection system. Redesign showed were structural behavior of retrofitted timber roof, double angle truss roof and gable frame roof structure showed better strength, stiffness and ratio of member force to self-weight.

PEMANFAATAN BUILDING INFORMATION MODELLING (BIM) PADA PERANCANGAN STRUKTUR BAJA TERHADAP BEBAN GEMPA

This study focuses on designing the steel structure construction toward earthquake load, which uses Istana Qur’an as a research object. Modeling and designing the steel structural building by using two different software, SAP2000, and Tekla Structure. In the making process, the authors made presumptions on workload according to Indonesian Design Standards such as minimum design loads, seismic load design, seismic load for steel structure design, and joints in steel structure. Not only from a structural strength view for human safety but also the construction time and material cost are also able to be estimated which is becoming faster and more affordable compared to implementing the conventional method. As a full analysis result, in this steel design, there are six different steel profiles were used for steel building construction. For instance, IWF 440.300.11.18 as the column, IWF 350.175.7.11 and IWF 250.125.6.9 as the beams, IWF 200.100.5,5.8 as the gable roof frame, UNP 150.75.9.12,5 as purlin and L 150.150.15 as collar tie.

Embodied Carbon Minimization for Single-Story Steel Gable Frames

As the construction industry, especially steel construction, contributes to a large portion of global greenhouse gas emissions, sustainable structural design has become a necessity to achieve the world vision of reaching net zero emissions by 2050. As steel portal frames are the most used structural system for single-story buildings, the main objective of this study is to determine the optimal steel portal frame configuration using prismatic and/or non-prismatic members to achieve the least embodied carbon. Five different portal frame configurations are considered under the effect of five distinct loading conditions. The results led to developing design charts consisting of contour plots showing the embodied carbon per unit of volume enclosed by the steel frame for different frame configurations, loading conditions, span lengths, and column heights. In addition, by increasing the number of member divisions, design variables, and non-prismatic segments, the average embodied carbon of the steel portal frames can be significantly reduced by about 14.34% up to 26.47% relative to the configuration with only prismatic members.

Optimal design of steel gable frames with tapered members using Enhanced Crystal Structure Algorithm (ECryStAl)

Steel gable frames are the most commonly used structural system to cover large spans. To obtain the optimal design of gable frames, many optimization algorithms can be used. Recently, a novel meta-heuristic optimization algorithm called the Crystal Structure Algorithm (CryStAl) has been proposed. The purpose of this study is to introduce the Enhanced Crystal Structure Algorithm (ECryStAl) and use it to optimize gable frames with tapered members. Several improvements are implemented in the algorithm including the dynamic crystal inclusion mechanism, grade-D crystal selection process, and a continuously narrowing search range. In addition to ECryStAl, the frames are optimized using four other meta-heuristic optimization techniques to compare their results with ECryStAl and investigate its effectiveness. The results statistically confirm that ECryStAl consistently converges to a more optimal design with less weight than the other meta-heuristics.

Aftershock fragility assessment of steel gabled frames consisting of web-tapered members

Due to the widespread construction of steel gabled frame systems throughout the world, many of them are located in regions with high seismicity and experience sequential strong events in the future. Previous studies have clearly shown that the damage caused by the mainshock modifies the overall strength and stiffness and consequently dynamic response to the aftershock. However, the current structural design process only considers the main seismic event, and the post-mainshock scenarios and their effects are generally ignored. In order to address this issue, in the present study, the mainshock incremental dynamic analysis (IDA) was first conducted on four SGFs. Then mainshock damage states based on the transient absolute maximum drift angle were considered, and aftershock incremental dynamic analysis analysis was performed on the mainshock-damaged structures. Aftershock fragility curves using probabilistic seismic demand models for transient absolute maximum drift angle and median IDA curves for residual absolute maximum drift angle were developed to compare intact and pre-damaged SGFs. The results showed that aftershocks significantly increase the vulnerability of short-period SGFs when higher damages are induced during mainshock, where the aftershock collapse capacity is reduced by up to 13% for the largest mainshock damage state. It was also found that in terms of aftershock collapse capacity associated with the residual absolute maximum drift angle, long-period SGFs require major realignment while short-period SGFs cannot be repaired.

A Collateral study on Optimization of Pre-Engineered building with Tubular sectional connection

Over the recent years, innumerable upheaval has been done in the field of steel construction industry, out of which pre-Engineered buildings (PEB) are one of the most remarkable ones. Pre-Engineered buildings are typical steel structures which are pre-fabricated and the designs are pre-determined which are contemplated to be more cost efficient, because of the tapered sections being utilized, in accordance with its bending moment requirement. These types of structures will not only be cost effective and environmentally friendly but also more flexible, thus eradicating the failure due to sequel of seismic forces. PEBs are generally industrial structures, which are designed for enormous spans. In this research work, the variation of structural behaviour of PEBs when it’s been embraced with considerably increased spans (30 m, 60 m and 90m) are compared and studied. In general, hot rolled tapered I-sections are used in erection of a PEB. Due to the inadequacy in connection configurations available, Pre- Engineered light weight cold form steel structures with tubular steel sectional connections are not well renowned. An attempt is also been made to bring out tubular sectional connections for the beam- rafter junction in all the PEBs deigned for 30 m, 60 m and 90m using E350 steel. Typical connections are proposed for both main frames and the gable frames of the PEB. The outcome of this study appears to be contended for at both the junctions in 30 m span and 60 m span, but 90 m main joint fails, due to the substantial bending moments developed across the major axis. So, these set of connections can be adopted for PEBs up to a moderate span, which helps in reducing the weight of steel that is been utilized in the construction, which successively foster sustainability.

Cyclic Behavior of Gabled Frames with Web-Tapered Columns and Rafters

Cyclic loading tests were conducted on three 1/2-scale, half-bay steel gabled frames (SGFs) to investigate their seismic performance. The three specimens with reduced joint stiffness were designed based on the prototype drawing shown in China design guideline 02SG518-1: specimen SV1 with a reduced thickness of the joint end-plate and bolt diameter, specimen SV2 with a reduced number of bolts, and specimen SV3 with a reduced bolt diameter. The load capacity, rotational stiffness, rotational capacity, and ultimate failure mode of specimens SV1, SV2, and SV3 were investigated. The experimental results showed that specimen SV1 failed due to the local buckling of the lower flange of the rafter, and specimens SV2 and SV3 due to the local buckling of upper flange of the rafter. The joint zone of all specimens kept well, indicating that the prototype joint had a large margin of safety. The hysteresis curves of all specimens were not full, and the ductility and energy dissipation capacity were limited. The end-plate thickness, bolt diameter, and steel grade affected the hysteresis performance of the SGF little. A refined finite element model was established, and the predicted results compared well with the test results. The test and analysis results demonstrated that there was slight utilization and distribution of post-buckling strength.

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.

Numerical modelling of apex connections in cold-formed steel gable frames

Cold-formed steel (CFS) sections have gained acceptance as primary elements in steel frames due to their exceptionally high strength to weight ratio. The main purpose of this research is to study the behavior of the apex joint in portals frame when subjected to monotonic vertical load. Numerical models for apex connections are developed using a finite element program to study the behavior of the connection. The numerical model is first verified by comparing its results with available experimental and numerical results. After the verification, the effect of several parameters on the connection performance was investigated. The parameters included the effect of the connecting gusset thickness and length as well as the effect of the distance between bolts. Moment-rotation relationships for different CFS apex connection numerical models were analyzed. The numerical models showed that the most significant modes of failure were gusset plate or beam web buckling. Increasing the distance between the two connected sections decreased the connection moment capacity, whereas increasing the thickness of the connecting plate enhanced the moment capacity.

Vertical component effects of earthquake and soil-structure interaction on steel gabled frames

With an increase in the width of the steel gabled frame (SGF) span, in general, the structural mass considerably increases, as a result of which the vertical ground motions can exert significant inertial force on the members of a structure. Although numerous studies have confirmed the destructive effects of the vertical component of earthquake on concrete and steel structures, no research has been devoted to the impact of this component on steel gabled structures yet. Hence, the findings of this research will, at best, unveil possible new dimensions of these types of structures. Moreover, the investigation into the behavior of such structures with regard to the effects of soil-structure interaction (SSI) can help gain a more accurate understanding of their behavior. To this aim, in the present paper, an incremental dynamic analysis (IDA) was conducted for the first time on four SGFs with spans of 20 m and 60 m and heights of 6 m and 12 m with and without consideration of the vertical component of earthquake as well as SSI. Results were collected in the form of multi-record IDA curves, summarized IDA curves, fragility curves and probabilistic seismic demand analysis (PSDA) curves, indicating that the vertical component of earthquake had a determinative role on the seismic performance of wide-span SGFs. This component causes the structure to reach the nonlinear region more quickly, raises the stiffness changes in the nonlinear region, enlarges the data dispersion and demand sensitivity, intensifies the softening behavior, reduces the dynamic capacity, raises the failure probability, enhances the uncertainty, increases the mean annual frequency (MAF) and accelerates the damage in such structures. However, SSI does not have any significant role in the seismic performance of SGFs; just partially leading to more conservative results, especially when they have wide spans. Besides, the results of the PSDA analysis showed that under similar conditions, short-period SGFs are more vulnerable than long-period SGFs and should be prioritized for retrofitting.

Geometry and sizing optimization of steel gable frames with tapered members

Steel gable frames with tapered members are often used to cover large-span spaces. To save material, the members of these frames are often considered I-shaped with linearly tapered webs. However, more savings in the material may be obtained if the design of structures is optimized. Many attempts have been made to optimize the size of these kinds of frames. Since optimizing the geometry may result in more savings, in this research, besides optimizing the sectional properties of tapered members, the height of the crown of frames has been considered as a design variable and optimized. The optimality criteria (OC) algorithm is used to find the optimal design. The Leibnitz integral rule has been employed to overcome the difficulties that arise when doing sensitivity analysis of non-prismatic members. This research shows that: a) the use of the OC algorithm provides less weight design than the meta-heuristic algorithms. b) Considering the geometry variables makes the structure more optimal.

Seismic reliability evaluation of steel gabled frames consisting of web-tapered members using joint analysis of hazard and fragility

Despite the wide application of steel gabled frame (SGF) systems in large industrial projects, the current literature lacks accurate information on their seismic performance to ensure satisfactory performance at different levels of earthquake intensity. Also, given the scant information on the structural performance and their seismic design parameters in most of the available guidelines, the use of joint analysis of hazard and fragility can be very important, since both the reference hazard on site and the structural performance are considered. To address this issue, in the present paper, incremental dynamic analysis (IDA) was performed using 20 ground motions on four SGFs and their results were collected in the form of fragility curves. Then to obtain the annual rate of exceedance, hazard curves of the study region were generated and combined with the fragility curves, and finally, the seismic reliability of SGFs was evaluated at design basis earthquake (DBE) and maximum considered earthquake (MCE) hazard levels. Seismic reliability results indicated that the available seismic design guidelines lead to a too conservative design for SGFs, especially when they have long periods, where at the MCE hazard level, long-period SGFs with about 58% safety margin do not even experience LS performance level. The results of this study can prove useful for a more efficient design of SGFs in seismic regions.

Probabilistic seismic assessment of steel gabled frames with web-tapered members under near-fault ground motions along strike-normal and strike-parallel components

The seismic assessment of steel gabled frames (SGFs) is of great importance and a key problem in any high-seismicity region, given the enormous costs of industrial equipment and the remarkable number of individuals working in such structures. Near-fault ground motions, especially their strike-normal component that usually contain a long-period pulse in the velocity time-history, can lead to a significant demand in these structures in comparison to the far-fault ground motions. Although numerous studies have confirmed the destructive effects of near-fault ground motions on concrete and steel structures, no research has been devoted to the impact of this ground motions on steel gabled structures yet. Hence, the findings of this research can unveil novel dimensions of such structures. In this regard, in the present paper, an incremental dynamic analysis (IDA) was conducted for the first time on four SGFs with the spans of 20 m and 60 m and heights of 6 m and 12 m using far-fault ground motions (OR set), as well as near-fault ground motions along the strike-normal and strike-parallel components (SN and SP sets, respectively). The results were presented in the form of multi-record IDA curves, summarized IDA curves, probabilistic seismic demand models (PSDMs) and probabilistic seismic demand analysis (PSDA) curves. The outcomes indicated that compared to far-fault ground motions, near-fault ground motions (especially pulse-like ones) produced significant changes on the seismic behavior of long-period SGFs, resulting in raises the changes of stiffness and demand sensitivity, reduces the dynamic capacity, enhances the data dispersion and uncertainty, and increases the mean annual frequencies (MAFs) in such structures. However, the results of PSDA analysis showed that under any type of ground motion (OR, SN and SP), short-period SGFs are more vulnerable than long-period SGFs and should be prioritized for retrofitting. Finally, the importance of combining the hazard curve of the study region with the results of IDA analysis of the structure in evaluating the seismic behavior of SGFs is highlighted.

Analytical investigation on the development of adaptive infilled gabled frames

Reinforced concrete infilled frame with brick masonry panel is becoming more common in recent days. Now a days this type structural frame is implemented mostly on the high-rise building because those buildings should be able to resist the lateral loads such as wind and seismic force hence, infilled frames are one of the most common lateral loads resisting system. In this study, two-dimensional single-bay, single-storey gabled infilled specimens were analyzed under static loading. The behavior of the reinforced concrete (RC) bare frame, RC infill frame with cement mortar interface is used and analyzed. In particular, the paper discusses the lateral stiffness of the frames and gives a comparative study between gabled frame and rectangular frame under static lateral load with varying parameters based on the obtained results such as displacement, lateral stiffness, bending moment and lateral load are carried out.

New enhanced colliding body optimization algorithm based on a novel strategy for exploration

Researchers use the improvement strategies to enhance the current version of optimization algorithms to establish the right balance between local and global search phases to escape from a local minimum in some NP-hard problems. Colliding Bodies Optimization (CBO) and its enhanced version (ECBO) use the concept of mass and energy conservation law based on Newtonian Classic Physics. The quality of mentioned algorithm performance can be improved by changing how the bodies collide with each other. New enhanced colliding bodies Optimization (NECBO) moves all bodies towards the best solution in consecutive iterations to increase the chance of accessing a better solution and exploring all promised solution space. In this paper, the recently developed meta-heuristic algorithm, so-called Enhanced Colliding Bodies Optimization (ECBO), and one new proposed version of ECBO (called NECBO), including a new mechanism for finding new solutions, and two hybrid versions of both methods mentioned above (ECBO, NECBO) are utilized for the optimal design of sloped-roof rigid frames with non-prismatic members. The steel sloped portal frames, or steel gable frames, are frequently used in industrial buildings, gyms, schools, colleges, fire stations, storages, hangars , and many other low-rise structures. The gable frames' weight and shape are considerably affected by the member cross-sections' properties. The optimization of steel portal frames with tapered web members is a hard NP problem because of discrete variables, multiple local optimum, and corresponding constraints. The obtained results show the capability of NECBO and its hybridized version with ECBO in find a better solution than the conventional ECBO and CBO. • New enhanced colliding bodies’ optimization (NECBO) is developed by altering how bodies colide each other. • Enhanced Colliding Bodies Optimization (ECBO) and the new proposed NECBO include a new mechanism for finding new solutions. • The hybrid version of both ECBO and NECBO are utilized for optimal design of gable frames with tapered members. • Optimization of gable rigid frames with tapered web members is performed. • Results obtained from this study show the capability of NECBO and its hybridized version with ECBO.

Testing and analysis of a full-scale steel-framed building including the consideration of structure-cladding interaction

A steel structure designed neglecting the effect of cladding was tested in three phases: i) without cladding, ii) with just the roof clad and iii) with both walls and roof clad. This paper deals with interaction of various structural components including cladding acting as a diaphragm. Detailed generic Finite Element Models (FEMs) have been developed for each phase of construction and showed excellent agreement with the test results. The paper details the difficulties associated with including cladding in design, not least of which is that the required ‘product’ (component) information is often out of date, incorrect or non-existent. The validated FEM is used to show that only around 10% of horizontal load applied at eaves level in the tested frame is resisted by the internal frames, and that the majority is transferred through parasitic stressed skin action to the much stiffer clad gable frames. A nonlinear analysis shows that for this structure the cladding is in little danger of premature failure. Nevertheless, the significant proportion of load resisted by the cladding should be taken as a warning to the construction industry that parasitic stressed skin action should not be ignored.