Browsing by Author "Orhan, Suleyman Nazif"

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Analyzing of Bolted Joints for Connecting Rectangular Hollow Sections in Reticulated Shells
(Taylor & Francis Ltd, 2023) Maali, Mahyar; Orhan, Suleyman Nazif; Sagiroglu, Merve; Cirpici, Burak Kaan
This paper investigates a novel joint method for connecting rectangular hollow section (RHS) members in reticulated shells. It is proposed to overcome the problem of connecting rectangular tubes using the traditional joint (cast steel joint) under dead and snow load. A case study is a structure in the eastern region of Turkey that was built on August 20, 2019. This museum-style structure is 40 meters long and 20 meters wide, with an oval shape. In the middle of the building, five tree-shaped columns were used. ANSYS is used to create a refined 3D solid model of the RHS joint. The moment-rotation results show that the proposed RHS joint (plate steel joint) for connecting rectangular hollow section members can be considered a semi-rigid connection and preferred due to its lower cost and weight. Moreover, the dissipated energy capacity has been raised by approximately 3.22 times when the plate steel type model has been used instead of the cast steel type. The stress ratios indicate that the connection stress in the Cast steel type model is lower than the stress in the Plate steel type model. As a result, the Cast steel type model is determined to be incredibly safe and more rigid than plate steel. Furthermore, since the resulting stress rates are lower than those of S355 steel, both models (cast and plate steel type models) can be used for connecting RHS.
A Biomechanical Study of 4 Different Sternum Closure Techniques Under Different Deformation Modes
(Oxford University Press, 2017) Orhan, Suleyman Nazif; Ozyazicioglu, Mehmet Hamit; Colak, Abdurrahim
OBJECTIVES: This study experimentally compares the efficiency of the 4 most preferred sternal closure tehniques, in 3 different deformation modes of the chest. METHODS: Polyurethane sternum models fixed by conventional wiring, steel band, ZipFix band and figure-8 wiring are tested statically under lateral distraction, longitudinal shear and torsional deformation modes. As a result, load-deformation curves are obtained. The closure efficiency of the techniques is then compared with respect to allowable load (corresponding to 2 mm displacement), rigidity, rupture load and rupture displacement. A comparison in terms of cost and ease of application has also been presented. RESULTS: The highest allowable load and rigidity values in simple tension and longitudinal shear are obtained by the steel and ZipFix band techniques, respectively. In torsion mode, the highest allowable load is provided by the ZipFix band and the highest rigidty is attained by the steel band technique. The highest rupture loads under simple tension, longitudinal shear and torsion modes are observed in ZipFix, steel band and conventional wiring, respectively. Steel band closure provides the least rupture displacement in simple tension as well as torsion, whereas ZipFix bands give the smallest rupture displacements in longitudinal shear. However, in every loading mode there were no statistically significant differences in allowable load, rigidity and rupture load values between the closure methods, and only rupture displacement values were statistically different for each method. CONCLUSIONS: Our results showed that conventional wiring is the most advantageous closing method when compared to the others.
Comparative Study of Progressive Collapse Behavior of Auxetic Concrete Cellular Structures Under Low-Velocity Impact Loading
(2024) Orhan, Suleyman Nazif; Solak, Kemal
The combination of auxetic behavior with concrete offers promising advancements in structural materials, providing unique mechanical properties that enhance impact resistance and energy absorption. The study investigates the mechanical behavior of auxetic concrete cellular structures, focusing on elliptic and peanut-shaped unit cells as well as their modified stiffener configurations, under low-velocity impact loading. To compare their impact performance, traditional and stiffened models were analyzed numerically using finite element solver ANSYS/LS-DYNA. The findings indicate significant differences between traditional and stiffened models. Stiffened models, such as SEC and SPC, exhibit higher maximum impact forces compared to traditional models like TEC and TPC. The introduction of stiffeners delays the zero-force phenomenon, resulting in extended energy absorption periods. The TPC model absorbed the most significant proportion of the initial impact velocity among traditional models, whereas the SPC model exhibited the highest energy absorption in models with stiffeners. The study highlights the potential of stiffened auxetic concrete cellular structures to enhance impact resistance and energy dissipation, making them advantageous for applications requiring high structural resilience. Further research into varying impact velocities and loading directions is recommended to optimize these structures for diverse conditions.
Design and Finite Element Analysis of a Novel Auxetic Structure
(2022) Orhan, Suleyman Nazif; Erden, Şeydanur
In this study, a novel auxetic structure, namely RDN, is presented in two- and three-dimensions. The unit cells are created by modifying the conventional re-entrant struc-ture and the 2D and 3D structures are formed by multiplying these unit cells. Finite element analyses are conducted to study the deformation mechanism of these struc-tures under uniaxial tension, and the mechanical properties of the structures are ob-tained. Also, a 3D unit cell is modelled with different strut thickness values to examine the effect of the strut thickness on mechanical properties. Numerical models are de-veloped using ANSYS/Static Structural software and linear elastic analyses are per-formed by applying small displacements to the structures. It is found that the 2D and 3D RDN structures possess a high negative Poisson’s ratio but relatively small stiffness compared to the other auxetics. The analyses of the 3D unit cells showed that increas-ing the strut thickness led to higher stiffness values but reduced auxetic behaviour of the structure.
Design, Fabrication, and Mechanical Analysis of Auxetic Cementitious Tubular Composites: An Experimental and Numerical Study
(Elsevier Sci Ltd, 2025) Solak, Kemal; Orhan, Suleyman Nazif; Kotan, Turkay; Ardahanli, Metehan
Auxetic cementitious composites exhibit enhanced mechanical performance such as high energy dissipation capacity and crack resistance. Such characteristics position them as promising materials for advanced construction applications. This study investigates the design, fabrication, and mechanical performance of novel auxetic cementitious tubular composites under quasi-static compressive loading. Auxetic cementitious tubular composites (ACTCs) were fabricated by casting glass fiber-reinforced mortar into a 3D-printed auxetic tubular mold. A combination of experimental and numerical methods was employed, including uniaxial compression tests, digital image correlation (DIC), and finite element modeling (FEM). This study further conducted a parametric analysis to examine the effects of geometric parameters, including wall thickness, porosity, and height, as well as varying loading conditions, on the failure mechanisms, stress-strain behavior, Poisson's ratio, and energy absorption characteristics of ACTCs. Experimental and numerical results confirmed the auxetic behavior of ACTCs under compressive loading. The stress-strain response exhibited distinct phases, including elastic deformation, peak stress, and post-peak softening. Failure mechanisms were primarily governed by plastic strain concentration, crack propagation, and densification. Cracks initially formed at the minor axis ends of elliptic perforations and propagated with increasing strain. FEM simulations accurately captured deformation behaviors and mechanical responses, aligning closely with experimental findings, while DIC analysis validated strain localization patterns. Parametric analysis results indicated that increased wall thickness enhanced peak stress and energy absorption, while porosity adjustments influenced both load-bearing capacity and auxeticity. The developed ACTC presents a novel design approach, proving its feasibility and exhibiting substantial potential for engineering applications.
Erzincan İli Zemin Büyütme Etkilerine Dayalı Mikrobölgeleme Çalışması
(2019) Ozyazicioglu, Mehmet; Donmezcelik, Kemal; Orhan, Suleyman Nazif; Ozkan, Mehmet Yener
Erzincan İli 1. derece deprem bölgesi içinde yeralmaktadır. Zemin yüzeyinden ana kayaya kadar alüvyon kalınlığı 1 km’yi bulanyerleşim alanında zemin büyütmesinin ayrıntılı olarak incelenmesinin gerekliliği açıktır. Bu çalışmada, Erzincan İl merkezi için birboyutlu kayma dalgası teorisine dayanan, eşdeğer-doğrusal zemin büyütme analizleri yapılmıştır. Çalışmada, zemin profillerinibelirlemek amacıyla, 1960-1980 yılları arasında Devlet Su İşleri Genel Müdürlüğünce (DSİ) açılmış ve derinlikleri 275 m’yi bulansondaj kuyularına ait veriler kullanılmıştır. Eşdeğer-doğrusal büyütme analizleri EduShake/ProShake programı kullanılarakgerçekleştirilmiştir. Kuyu noktalarında oluşturulan profillerde, 8 farklı anakaya hareketi kullanılarak, zemin yüzeyinde oluşanortalama hareketin ivme-zaman geçmişi ve ortalama PSA (görünür spektral ivme) grafikleri oluşturularak Türk DepremYönetmeliğinde (2007) verilen tasarım spektrumu ve ana kaya mostrası PSA ile karşılaştırılmıştır. Belirli periyotlar için, spektral ivmecinsinden büyütme oranları (ana kaya mostrası hareketine göre) hesaplanmıştır. Sondaj noktalarının temsil ettiği alanlarda,büyütmeye maruz kalması beklenen yapı periyotları haritada gösterilmektedir.
Evaluation of Sternum Closure Methods by Means of a Nonlinear Finite Element Analysis
(Sage Publications Ltd, 2019) Orhan, Suleyman Nazif; Ozyazicioglu, Mehmet Hamit
The main purpose of this study is to develop a validated three-dimensional finite element model of sternum closure techniques. For this aim, the finite element method analysis results of three closure methods were compared with experimental test results. Also, three more closure techniques are simulated numerically to study the effect of the number of wires used in the manubrium and xiphoid regions. A three-dimensional model of polyurethane sternum foam was created based on computed tomography images. Six different closure techniques using steel wire, steel bands and ZipFix bands were modeled on the sternum and transferred into a three-dimensional finite element model. The sternum was modeled as an isotropic bilinear-elasto-plastic material, and nonlinear contact conditions were applied. The models were analyzed under lateral distraction loading, and load-displacement curves were obtained from displacements at the incision line. Allowable loads and stiffness values of the methods were evaluated from these curves. The results showed the importance of the including material as well as geometric nonlinearities in the simulations to obtain realistic results from the numerical analyses. Also, the analyses showed that closures that include steel or ZipFix bands are superior to conventional wiring, and addition of a single wire at the manubrium and xiphoid regions significantly improved the efficiency of the closure techniques.
An Experimental and FEA Investigation of Deformation Characteristics of Additively Manufactured Ti6Al4V Lattice Structures
(Elsevier, 2025) Kaya, Gurkan; Yildiz, Fatih; Solak, Kemal; Orhan, Suleyman Nazif
This study presents a comprehensive experimental and numerical investigation of the mechanical properties and deformation characteristics of additively manufactured Ti6Al4V lattice structures fabricated via Laser Powder Bed Fusion (L-PBF). Two lattice configurations, face-centred cubic (FCC-Z) and body-centred cubic (BCC-Z), both containing struts oriented along the X, Y, and Z directions, were designed with varying porosity levels of 50 %, 60 %, 70 %, and 80 %. The static compression tests were conducted to evaluate the compressive strength, deformation behaviour, and energy absorption capabilities of the lattice structures. Additionally, finite element analysis (FEA) was employed to simulate the deformation mechanisms and predict the mechanical responses under compressive loads. The results revealed that as porosity decreased, both FCC-Z and BCC-Z structures demonstrated increased compressive strength and energy absorption efficiency. Notably, the FCC-Z lattices exhibited superior mechanical performance in terms of compressive strength, specific energy absorption (SEA), and crushing force efficiency (CFE) compared to the BCC-Z lattices. The deformation mechanisms were characterised by layer-by-layer fractures in FCC-Z structures and shear band formation in BCC-Z structures. Furthermore, the FEA results closely aligned with the experimental data, validating the accuracy of the simulation in predicting peak forces, displacement trends, and failure mechanisms. This work provides new insights into the optimisation of Ti6Al4V lattice structures, particularly for applications requiring high energy absorption and mechanical efficiency, such as in the biomedical and aerospace sectors.
Experimental Behavior of Cold-Formed Stainless Steel Screwed Beam-Column Connections at Post-Fire Condition
(Springer International Publishing AG, 2021) Cirpici, Burak Kaan; Orhan, Suleyman Nazif; Kilic, Mahmut; Maali, Mahyar; Sagiroglu, Merve
Herein this paper, the experimental behavior of the cold-formed stainless steel screwed beam-column connection with the post-fire condition is presented by performing eight experiments. The beam structural members have been heated beginning from room temperature to 600 degrees C remaining at this temperature for 5-h and letting them cool down back to the room temperature. Energy dissipation capacity, moment-rotation behavior and ductility of the joint under the post-fire condition have been examined by various beam thickness, gusset thickness and with and without stiffeners. The obtained results show that energy dissipation, and rotation decrease due to the sudden breakage of the screws with the increase in gusset plate thickness. Contrast to this outcome, stiffness had a decrease trend, whereas rotation increases when using stiffeners. With the increase of beam thickness, rotation had an increase behavior. Failure modes under the post-fire condition have been compared with the ambient temperature condition. The results indicate that the pre-heating before loading influences the screws' strength more causing a laceration around the screws hence the total collapse of the connection. As using stiffeners increases the strength of the beam at ambient temperature condition, it also gives an advantage under fire condition. Therefore, rare screw deformation has been obtained depending on the beam thickness and gusset plate thickness while wrinkle of the gusset plate and torsion of the beam has been observed.
Influence of Processing Parameters and Testing Temperatures on Thermomechanical Coupling Properties of Additively Manufactured Ti6al4v-Eli Auxetic Structures: Experimental and Numerical Study
(IOP Publishing Ltd, 2026) Solak, Kemal; Tekdir, Hilmi; Orhan, Suleyman Nazif; Yetim, Ali Fatih
This study investigates the effects of processing parameters and testing temperatures on the mechanical properties of auxetic structures fabricated from Ti6Al4V-ELI using Laser Powder Bed Fusion. Three distinct sets of process parameters (Set 1: 50 W-400 mm s-1, Set 2: 75 W-800 mm s-1, and Set 3: 100 W-1200 mm s-1) were employed to fabricate peanut-shaped auxetic structures, which were subsequently tested at temperatures of -20 degrees C, 25 degrees C, 100 degrees C, and 200 degrees C. Digital image correlation was employed for detailed strain analysis, while the fabricated auxetic structures were further characterized using x-ray diffraction, scanning electron microscopy, and Vickers hardness testing. The experimental results were validated through thermomechanical finite element simulations, followed by a parametric study to examine the influence of geometric parameters and testing temperature on the mechanical performance of the auxetic structures. According to the test results, Set 3 exhibited the highest peak force, whereas Set 1 demonstrated the lowest. Furthermore, Set 2 achieved maximum elongation at 200 degrees C. The investigated structures exhibited auxetic behavior under varying testing temperatures and processing parameters. The structure fabricated with Set 1 parameters demonstrated the highest auxetic response, whereas that produced with Set 3 parameters exhibited the lowest. The parametric study revealed that the mechanical properties of auxetic structures are influenced by the auxetic unit cell dimensions, pattern distribution, and testing temperature while also being sensitive to processing parameters, thus offering the potential for tailored optimization and guiding future material design.
Numerical Investigation of the Fire Behavior of Storage Rack Systems Protected by Intumescent Coating
(Amer Chemical Soc, 2022) Cirpici, Burak Kaan; Orhan, Suleyman Nazif; Yazici, Casim; Ozkal, Fatih Mehmet
Using a finite element strategy, this study investigates the behavior of beam-to-column connections in storage rack systems exposed to high temperatures. The purpose of this research was to develop moment-rotation (M-theta) curves after painting various structural members with varied config-urations in order to evaluate the performance of intumescent-coated beams, uprights, and connectors, which are components of storage rack systems. Within the scope of this work, finite element analyses were carried out in two stages. First, thermal analyses were performed using the transient thermal analysis system of ANSYS Workbench software to estimate the ultimate temperatures of the beam, upright, and connector, which were painted with 1 mm thick paint and exposed to standard (ISO-834) fire. The results were then compared to the Eurocode 3 Part 1.2 with a satisfactory agreement. In the second stage of the analysis, a total of 9 possible alternative models were investigated in the static structural analysis system, reflecting the effect of applying fire protection to the different portions of the rack system. Since the most critical stress level is achieved around the connector tabs, it has been observed that protection of the connector in individual or binary conditions provides higher performance while protection of the beam causes divergent joint behavior. Additionally, comparison of fully protected and unprotected conditions presents an increment of more than 7% on the joint's ultimate moment capacity and initial stiffness, which is an explicit contribution of the intumescent coating to fire resistance.
Numerical Investigation of the Mechanical Properties of 2D and 3D Auxetic Structures
(IOP Publishing Ltd, 2022) Orhan, Suleyman Nazif; Erden, Seydanur
Auxetic materials and structures have a negative Poisson's ratio and it is this unique property that differentiates them from traditional materials. In recent years, three-dimensional (3D) auxetic structures have attracted considerable interest with the emergence of advanced manufacturing technologies. Many studies have been carried out to determine the mechanical properties of the existing 3D structures or improve and develop new ones, and extensive research is ongoing. This paper presents a comparative numerical study of two-dimensional (2D) and 3D geometries of four different auxetic structures, namely: elliptic holes, lozenge grids, re-entrant and arrowhead. Among these structures, elliptic holes and lozenge grids are designed and studied in 3D for the first time in this study. The structures are analysed under axial tension and the Poisson's ratio, Young's modulus and stiffness values are obtained from linear finite element model analysis. In addition, the unit cells of the 3D structures are examined. The findings showed that the elliptical holes structure exhibits a higher negative Poisson's ratio than other auxetics and the 3D re-entrant and 2D arrowhead structures outperform the other auxetics with respect to the Young's modulus and stiffness values.
Performance Evaluation of Peanut-Shaped Tubular Auxetics with Enhanced Stiffness: A Finite Element Study
(IOP Publishing Ltd, 2023) Solak, Kemal; Orhan, Suleyman Nazif
Auxetic materials or structures possess a negative Poisson's ratio in contrast to conventional materials, and they shrink or expand transversely under uniaxial compression or tension, respectively. These unique deformation features leads to enhance the mechanical properties compared with the conventional materials. Auxetic tubular structures are of significant interest in the literature because of their superior mechanical qualities, applicability and extensive application. Various auxetic tubular structures with different geometries have been proposed and examined before including conventional peanut-shaped tubular structures. However, application of the peanut-shaped structures is limited due to their low stiffness. In this study, it is aimed to enhance the stiffness of the peanut-shaped tubular auxetic by either adding stiffener to the conventional structure or rotating the unit cell of the structure by a certain angle. Also, the effect of the above-mentioned modifications on the Poisson's ratio of the structure is investigated. A total of 12 different peanut-shaped auxetics are modelled and the elastic behaviour of these structures under uniaxial compression is compared numerically using finite element simulation. As a result of this analysis, it is observed that both the Poisson's ratio and stiffness values obtained from the models utilising stiffener were higher than the values obtained from their conventional counterparts. Besides, it is seen that the stiffness values increased while the Poisson's ratios decreased with the rotation of the unit cell in all of the peanut-shaped tubular auxetics.
Post-Fire Behaviour of Screwed CFS Frames Protected by Intumescent Coatings
(Springer India, 2023) Maali, Merve Sagiroglu; Senger, Dogukan; Maali, Mahyar; Cirpici, Burak Kaan; Orhan, Suleyman Nazif; Kilic, Mahmut
Thinner and lower-cost building elements have begun to be developed as technology advances around the world and in our country. Cold-formed steel construction elements are one of the structural elements produced. Although its use is growing, cold-formed steel frames have limited resistance to fires, which is a significant concern in buildings. Great damage will be incurred if precautions against fires in these structures are not adopted. There are various insulation materials in cold-formed steel structures to ensure the safety of life and property against fire. In this experimental study, screw column-beam joints' post-fire behavior was investigated by using fire-protective intumescent paint on frames made of cold-formed steel structures. The beams formed by placing a gusset plate between the cold-rolled C200 profiles back-to-back are connected with self-tapping screws. A total of ten experimental setups depending on stiffening plate were created using C200 beam profiles with two different wall thicknesses, three different gusset plate wall thicknesses, and two different paint thicknesses. All of the ten full-scale specimens were heated in the furnace according to the ISO834 standard fire. The behavior of the specimens after the fire exposure, including the moment-rotation curves and failure modes, was determined by arranging the data into four groups for comparison. In addition, the current studies existing in the literature on the behavior of unprotected members in fire were compared to the outcome reported in this paper. As a conclusion of the test results, the intumescent paint applied as a fire protection to the structural connections of the cold-formed steel members improved their fire resistance considerably.
Quasi-Static Crashworthiness Behaviour of Auxetic Tubular Structures Based on Rotating Deformation Mechanism
(IOP Publishing Ltd, 2024) Solak, Kemal; Orhan, Suleyman Nazif
Auxetic materials have attracted significant interest due to their exceptional mechanical characteristics and distinctive deformation modes. Nevertheless, the practical use of these materials in engineering is constrained by their limited ability to absorb energy. Thus, enhancing the energy absorption (EA) capabilities of auxetic materials is crucial to expand their range of potential applications. In this study, the EA capabilities of auxetic tubular structures with rotating deformation mechanisms are examined, with a specific emphasis on three different perforation shapes: elliptic, peanut, and square, along with their modified versions incorporating stiffeners. The study employs a combination of experimental testing and numerical modelling, utilising ANSYS/LS-DYNA to evaluate various crashworthiness parameters. These parameters include total EA, specific EA, maximum crushing force, and crushing force efficiency, all of which are assessed under quasi-static compression conditions. The research highlights the importance of perforation shape and stiffener incorporation in enhancing crashworthiness. Results show that elliptic perforations exhibit superior EA and stiffened auxetic models outperform conventional ones in terms of crash absorber performance. The presence of stiffeners significantly improves the ability of tubular structures to withstand crushing forces. Furthermore, the study validates the numerical model against experimental findings, demonstrating a high level of agreement in terms of crushing force-displacement, EA, and failure modes. The research provides valuable insights into the design and performance of crashworthy structures and offers potential applications in various fields where impact resistance and EA are critical.
Reformative Effects of Intumescent Coating on the Structural Characteristics of Cold-Formed Steel
(American Chemical Society, 2022) Yazici, Casim; Ozkal, Fatih Mehmet; Orhan, Suleyman Nazif; Cirpici, Burak Kaan
Intumescent fire-resistive coatings are a more recent type of passive fireproofing thin film that swells many times its initial applied thickness, generating an insulating char that functions as a thermal barrier between the fire and structural steel. It keeps the heat of steel members from reaching critical levels and aids in the structural integrity during a fire. They are architects and designers' favorite choice for passive fire protection of load-bearing steel frame structures because of their aesthetic look, versatility, rapidity of application, and ease of inspection and maintenance. In this study, axial tensile, thermal conductivity, and hardness tests have been performed on S235 cold-formed steel specimens that were exposed to increasing temperature periods. The mechanical behavior of coated and uncoated specimens was investigated over the modulus of elasticity, yield strength/strain, and ultimate strength/strain values for all temperatures. As a result of the research, gradually increasing changes were observed in the mechanical properties of coated and uncoated specimens at increasing temperature levels, compared to each other. However, performance increment on the coated specimens was limited in terms of strength and strain characteristics than expected. Two essential reasons for this conclusion are that the specimens were exposed to heat for a long time after reaching the target temperature and also that the wall thickness of the specimens was thinner with respect to the usual application method of the protective coating. In order to examine the structural properties of the test specimens after elevated temperature effects, thermal conductivity measurement was also performed. Temperature difference between coated and uncoated surfaces provided a benefit in the range of 29-56% due to the coating. Lastly, microstructure imaging techniques demonstrated grain coarsening and no crack development with the increase in temperature.
Structural Performance of Different Baseplate Configurations in Storage Rack Systems
(Springer Heidelberg, 2025) Yazici, Casim; Gurbuz, Muhammed; Orhan, Suleyman Nazif; Solak, Kemal; Ozkal, Fatih Mehmet
The successful transfer of complex loads from a storage rack system to the concrete slab is closely related to the performance of the connection between the baseplate and the upright. The relationship between moment and rotation strongly influences the performance of this connection. Various factors, including the arrangement and quantity of anchor rods and the direction of loading, impact the moment-rotation behavior in the baseplate connection. However, predicting the moment-rotation behavior of the baseplate-upright connection, considering the different loading directions and anchor configurations commonly found in commercially available storage racks, has not received sufficient attention. Thus, this study aims to investigate the behavior of five distinct baseplate models that employ two or three anchor bolts, subject to two different loading directions. The investigation is carried out through rigorous numerical simulations and meticulous experimental testing. By focusing on the moment-rotation curves resulting from the applied loads, the study aims to gain valuable insights into the performance of the baseplate-upright connections. Additionally, the validated finite element model is employed to examine the distribution of principal stress, providing crucial information about the connection's structural integrity and potential failure points. Certain configurations were observed to outperform others in terms of energy dissipation and favorable moment-rotation characteristics. The configuration with three bolts located at the back of the upright (3B-B) outperforms with higher energy dissipation capacities and more favorable moment-rotation characteristics, while the configuration with two bolts vertically located at the back of upright (2B-V) is inferred to have inferior performance.