Tension Zone Research Articles

Behavior of TOBs bolted curved T-stubs to steel tube with internal stiffener

Internal stiffeners can effectively enhance the structural performance of Thread-fixed One-side Bolts (TOBs) bolted steel beam to circular tubular column connection by increasing the out-of-plane flexural capacity of the column wall and the anchorage length of the TOBs. Five TOBs bolted T-stubs to circular steel tube specimens with three different forms of internal stiffeners, substituting the tension zone of beam to column joint, were designed and tested in this paper to determine a reasonable form for the internal stiffener. Test results showed that the strengthened specimen could prevent undesirable plastic deformation of tube wall and hole threads shear failure. The Type-II stiffener consisting of an internal steel tube with a longitudinal rib performed the optimum strengthening effect. Finite Element analysis is conducted to analyze phenomena that could not be directly observed during the test. It is found that the hole threads in the stiffener wall provide considerable anchorage force, which may be larger than that provided by the hole threads in the steel tube in the late loading stage. Parametric studies are also conducted on the wall thickness, rib thickness, and installation gap of the Type-II stiffener. The results show that the stiffener wall thickness is the main factor affecting the strengthening effect and the installation gap should be controlled within 2 mm to ensure the strengthening effect. Finally, design approaches are presented to predict the carrying capacity of the strengthened connection, and the validation against the test and FE results shows reliability and stability.

The Influence of a Damaged Concrete Cover on the Behavior of a Simply-Supported Beam

The concrete cover is a part of the concrete that provides the required protection for the reinforcing steel within the required element from external effects. This concrete cover can be damaged for an assortment of reasons, one of which is environmental factors. As a result, this research focused on the effect of worn concrete covering on the structural response of beams. Moreover, the possibility of repairing or replacing this concrete cover with a cement material was done by testing seven beams with the exact dimensions (2700 mm long, 250 mm deep, and 140 mm wide). The first specimen was a control specimen, while in the remaining specimens, a part of the concrete cover was removed in the midspan region with a length of 600 mm and in different formats. The part below the neutral axis (tension zone) was removed in the first two specimens. The part above the neutral axis (the compression zone) was removed in the second two specimens. The whole cover was removed within the specified distance for the other two specimens. In one out of every two of these six specimens, the removed concrete cover was replaced with cementitious material. A flexural test was performed for all specimens, and the conclusion was reached that damaging or removing the concrete cover from the tensile region (below the neutral axis) is less harmful than from the compression region since the beam is often designed as a cracked section. Also, removing the concrete cover from the compression region gives cracks a greater width than removing the concrete cover from the tension region at the same loading level. In the case of replacing the concrete cover with a cementitious one, if the replacement is in the compression zone, it will result in cracks when loading with a width greater than that of the rest of the cases. For specimens that removed their concrete covers from the tension zone, compression zone, and the whole section, the failure loads decreased by 39%, 20%, and 23%, respectively, concerning the control beam. In contrast, all these specimens were repaired with cementitious materials, with an ultimate load capacity approximately equal to the control beams. From these results, any damaged concrete cover for beams in any zone with cementitious materials having high strength and a good bond with old concrete sections can be repaired. Doi: 10.28991/CEJ-2023-09-07-09 Full Text: PDF

Bimodular Microbeams Based on the Elastic Foundation: Free Vibration

The paper uses the modified couple stress theory to study the free vibration model of bimodular microbeams with an elastic foundation. Microbeams behave differently in the tension and compression zones due to the bimodular property, and the neutral layer depends on the sign of the bending moment. By figuring out the effective strain formula and applying Hamilton’s principle, the governing equation for free vibration can then be derived. The equation takes into account the size effect, the foundation parameters, and the bimodular property’s effects. Using the differential quadrature method, it is examined how the foundation parameters and the material length scale parameters affect free vibration. The findings indicate that frequency increases as parameter size increases.

Numerical Modeling and Design Method for Reinforced Polyvinyl-Alcohol-Engineered Cementitious Composite Beams in Bending

The polyvinyl-alcohol-engineered cementitious composite (PVA-ECC) is a superior cementitious material when used for tension and flexural loading. The utilization of PVA-ECC in the tension zone can prevent the development of wide cracks and increase the flexural resistance of reinforced PVA-ECC members. In this paper, a nonlinear finite element model is established to simulate the behavior of PVA-ECC beams in bending. In the model, the constitutive models for PVA-ECC in compression and tension are employed by simplifying them as piece-wise linear models, and the bond between the reinforcing bar and PVA-ECC is also considered. The load–deflection curve and failure mode of beams can be obtained from the finite element model. Comparisons between numerical and experimental results show that the developed numerical model can estimate the ultimate load and failure mode of beams with reasonably good accuracy. After evaluating the accuracy of the finite element model, parameter analysis is conducted to investigate the effects of the reinforcement ratio, steel strength grade, and mechanical properties of PVA-ECC on the flexural behavior of reinforced PVA-ECC beams. The numerical results conclude that the effects of reinforcement ratio on the peak load, stiffness, and deflection are obvious while the influence of steel grade is mainly on the peak load. The tensile localization strain of PVA-ECC mainly affects the ductility of the beam. Furthermore, a design method is proposed based on the plane-section assumption to calculate the ultimate load of reinforced PVA-ECC beams, in which the contribution of PVA-ECC to the moment resistance of beam sections is considered. Comparisons between existing design methods and the proposed method indicate that the ultimate load of beams can be predicted more accurately by considering the tensile strength of PVA-ECC in the tension zone.

Collapse mechanism of three-dimensional modular steel buildings: Effect of steel wall and difference with traditional steel frame

This paper presents a numerical study on the collapse performance of 3-D MSB (modular steel building) in four module-removal scenarios: removals of a single corner module, single edge module, single interior module, and two edge modules. The final global deformation, resistance-displacement relationship, inter-module connection force, and contribution of the steel wall of the MSB structure are reported. The difference of the collapse mechanism between the MSB structure and traditional steel frame structure is also elaborated. It is found that using a 2-D model will significantly overestimate the deformation of the MSB structure in corner module loss due to the neglect of the floor slab, ceiling slab, and steel wall in the orthogonal direction. Under the interior and edge module loss circumstances, significant compression buckling can be observed in steel walls of the structure. In the condition of corner module loss, however, diagonal tension zones are found in the steel walls. The contribution of the steel wall to the resistance of the MSB structure in different module-removal scenarios is about 35%–66%. The existence of the steel wall delays the development of the tensile force and even results in compression force in the connection. In the two-edge module-removal scenario, when the steel wall is not considered, the MSB structure performs as a traditional steel frame, in which all connections between the adjacent modules are in tension. However, when the wall thickness increases, the tension in connections at the upper storey of the MSB structure decreases and may even changes to be in compression.

Structural Behavior of Reinforced Concrete Hollow Beams under Partial Uniformly Distributed Load

A Longitudinal opening is used to construct hollow core beam is a cast in site or precast or pre stressed concrete member with continuous voids provided to reduce weight, cost and, as a side benefit, to use for concealed electrical or mechanical runs. Primarily is used as floor beams or roof deck systems. This study investigate the behavior of six beams (solid or with opening) of dimension (length 1000 x height 180 x width120mm) simply support under partial uniformly distributed load, four of these beam contain long opening of varied section (40x40mm) or (80x40mm). The effect of vertical steel reinforcing, opening size and orientations are investigated to evaluate the response of beams. The experimental behavior based on load-deflection measured at central and quarter of tension zones. The experimental test result shows the presence of Hollow decrease the load carrying capacity by about (37.14% to 58.33%) and increased the deflections by about (71.6% for (Hollow ratio 7.4%) to 75.5% for (Hollow ratio 14.8%)) for same applied loadcompared with solid beams with the same properties. The increase shear steel reinforcing will decrease all the deformations at all stages of loading, but particularly after initial cracking and give enhancement in ultimate load capacity of beams by about 31.5% with increasing the amount of shear steel reinforcing by about 50%. Finally, ductility is increased in all cases under partial uniformly distributed load when hollow ratio decreased by about 50% or increased in shear steel reinforcing by about 50%

Stability Analysis of Gentle Dip Thick Ore Body Mining Based on the Integration of SURPAC-FLAC3D

Issues of large exposed roof area, poor stability, and significant roof support workload are prevalent in the mining of metal ores with gently inclined thick bodies. In response to these challenges, a downward cemented fill mining method has been proposed to enhance the stability of the surrounding rock and filling body. By integrating SURPAC and FLAC3D software, a three-dimensional numerical model that conforms to the actual geological morphology of the mining area was established. Numerical calculation results indicate that after the first stage of ore body excavation, the surrounding rock settlement mainly occurs in the roof and the hanging wall of the -65m level, with the hanging wall settlement primarily concentrated between the 3rd and 4th vertical exploration lines. The filling body demonstrates a weak compressive stress capacity, leading to a gradual transition of compressive stress to the surrounding rock of the mine stope. As the excavation level increases, the compressive stress on the pillars also increases, forming a compressive stress concentration area at the -65m level. A mixed plastic zone of shear and tension is generated in the roof and hanging wall, while a shear plastic zone is present in the inter-pillar area. The findings of this study offer valuable insights to ensure the safety of mining in gently inclined thick ore bodies.

Optimum depth of a lower concrete grade at the tension zone in a two-layer reinforced concrete beam

This paper presents the results of an investigation into the optimum depth of the lower concrete grade (LCG) at the tension region in a two-layer reinforced concrete beam. A total of nine (9) simply supported two-layer RC beams (1100 x100 x150 mm) were studied. Two 8 mm and two 6 mm diameter rods were used as reinforcement at the bottom and top of each two-layer beam, respectively. The beam samples were grouped into two: the first group comprises two-layer RC beams produced with 1:2:4 as the higher grade and 1:3:6 as the lower grade; the second group comprises two-layer RC beams cast with 1:2:4 as the higher grade and 1:4:8 as the lower grade. The depth of LCG adopted for each group is 25 mm to 100 mm at a step of 25 mm out of the total beam depth of 150 mm. The beams were subjected to two-point static loading to evaluate the load resistance and deflection. The results show that the greater the depth of the layer under compression, the stiffer the beam. The two-layer RC beam has an equal loading carrying capacity as the beam made entirely of higher grade. The depth of the layer of RC beam under tension in two-layer beams should be kept between 40 and 50% of the overall beam depth, which would be desirable structurally.

Study on the Style Design and Anchoring Mechanism of Enlarged Head Anchors

To resolve insufficient traditional bolt supports due to the complexity of geological conditions, the optimal design of an expanded head bolt was investigated by using theoretical calculations and experiments. The results show that the drawing capacity of an expanded head bolt is affected by the bearing capacity of front and rear ends, side bearing capacity, and side friction resistance. For a circular anchor bolt, stepped anchor bolt, and semi-ellipsoidal anchor bolt, with an increase in the front section’s radius, the lateral friction resistance of the inner anchor section is gradually shared by the bearing force of the front end of the inner anchor section; the bearing effect of the front end of the inner anchor section is enhanced; and the pulling performance of the anchor bolt is enhanced. Therefore, the pulling force of the circular anchor bolt is at the maximum, followed by the stepped anchor bolt, and the semi-ellipsoidal bolt is at the minimum. The increase in the rear section can provide greater lateral friction resistance and end-bearing force. Compared with cylindrical enlarged head anchors, the circular, stepped, and semi-elliptic enlarged head anchors have a smaller front section but a larger rear section, and the reduction in the front section’s bearing capacity is less than the increase in the side bearing capacity and rear-end bearing capacity; thus, the cylindrical bolt has the lowest pulling force. Compared with the front radius, the back radius has more influence on the drawing ability of the enlarged head anchor. The longer the inner anchorage section, the larger the distribution range in the compression zone that is formed in the soil body and the smaller the range in the tension zone that is formed in the rear. The increase in the length of the inner anchorage section is conducive to improving the reinforcement effect of the soil in front of the anchorage section in the bolt. Therefore, this parameter plays an important role in the redistribution of the soil in front of the force. The ultimate pull-out force of a circular table-shaped tensile bolt is the highest, followed by the stepped bolt, and the semi-elliptic bolt comes in third, with the cylindrical bolt exhibiting the lowest pull-out force; the circular table-shaped enlarged head anchor constitutes the best style design.

Understanding the acceleration impact of load and flowing water on the chloride ion transport properties of fly ash-based geopolymer concrete

In this study, the acceleration impact of load and flowing water on the Cl− transport properties of fly ash-based geopolymer concrete (FABGC) was studied for concrete in a complex environment. The results showed that when the erosion age remained unchanged, the concentration of Cl− gradually decreased, and the proportion of bound Cl− increased with an increase in depth from the FABGC surface. At a constant depth from the FABGC surface, Cl− mainly exists in the form of free Cl−. Both flowing water erosion and loading promoted the transport of Cl−, and their combined effect was the primary factor influencing ion transport in the tension zone. When its content in FABGC is high, Al will change the gel structure in FABGC, thus inhibiting the transport of Cl−. A Cl− transport model considering multiple factors (such as the bound Cl−, load, porosity, and flowing water) was established, and its rationality was verified.

DETAILED ANALYTICAL STUDIES OF CUTTINGS FROM OIL AND GAS WELLS AS A MEANS OF IMPROVING THE QUALITY OF GEOLOGICAL EXPLORATION AND DRILLING OPERATIONS

For date we can observe nearly full exhaustion of the largest deposits of hydrocarbons that are easy constructed in geological way, that’s why today’s exploration work is oriented on searching of small deposits and non-traditional reservoirs. For searching and development of such deposits it is necessary to apply the high-technological methods of geologic and geophysical research, previously provided mainly by foreign companies. In this regard, there is an acute need for the emergence of new costeffective approaches for the providing of geological exploration works. In such conditions the exploration of cuttings material by the modern analytical methods may become one of the main drivers of new direction of geological works because it lets to process the results directly while drilling and receive the information in real time. The main advantages of cuttings are: the possibility to study the section of well with equal discretization distance; minimal terms of sample preparation and partial conduction of analytical studies directly during the drilling process, sampling of cuttings does not affect on the technology of well construction and does not require the conduction of supplementary tripping operations, detail study of cuttings may replace highcost methods of geophysical logging and allows to conduct the correct interwell lithological and stratigraphic correlation while cluster drilling online. However, the complex and profound study of cuttings material allows to characterize and estimate the quality of reservoirs and caprocks; study the rock sources of oil and gas and their properties; built the detailed lithological, facial and mineralogical models; detect and localize zones of latent faults and tectonic tensions, achieve the reliable stratigraphic dating; to provide the most effective tracing of horizontal production wellbore. The exploration of cuttings is actual as for old oil and gas regions, as for new oilfields with difficult construction, because it allows to achieve the qualitative geological information all over the section. Within the conditions of sanction pressure (including the import of equipment for searching and production of hydrocarbon) from the west countries, the complex exploration of cuttings material may not only complete the leakage of geological information, but also provide its growth.

Experimental Investigation on Steel Fiber Reinforced Concrete

The objective of the study is to analyze systematically the effects of steel fiber reinforcement in concrete. Concrete were prepared using M30 grade concrete and looked end glued steel fiber with aspect ratio of 80 were added at a dosage of 0.75% , 1% , 1.25% volume fraction of concrete. The fiber reinforcement effects were analyzed for different types of distribution in the concrete beam Fibers were dispersed in two different ways either homogeneously in concrete sections or localized in the tension zone or laid parallel the beam axis. The mechanical properties such as the flexural strength using a third point loading and compressive strength property were determined. Load vs deflections were plotted for various fiber concrete specimens and toughness evaluations were made systematically using graph software an order to quantify the energy absorbing mechanism. Test result were compared with that of Plain concrete specimen and the relative improvements on the toughness were measured. Significant conclusions were drawn and comparative analyses on the post elastic deformation capacity of different concrete specimens were measured. Key Word: Steel Fiber, Toughness, Compressive Strength, Split tensile strength.

Self-sensing GFRP-reinforced concrete beams containing carbon nanotube-nano carbon black composite fillers

This study investigated the self-sensing behavior of nonconductive glass fiber reinforced polymer (GFRP) reinforced concrete beam incorporated with electrostatic self-assembly carbon nanotube-nano carbon black (CNT-NCB) composite fillers (CNCFs) under monotonic and cyclic flexural loadings. The CNCFs feature synergistic effect of long-range conduction for fibrous CNTs and short-range conduction for granular NCBs, as well as their good dispersibility. Self-sensing signals in the compression and tension zones of the concrete beams were synchronously recorded through embedding stainless steel gauze electrodes in these sensing zones. Experimental results showed that incorporating CNCFs can achieve low and stable electrical resistivity (ranging from 33 to 76 Ω‧cm) for the concrete beams. Under monotonic flexural loading, the largest resistivity variation was observed in the case of concrete beam with 1.8 vol.% CNCFs, and the magnitude of fractional changes in resistivity (FCR) reached nearly 286%. Moreover, FCR in tension zone was more pronounced than that in compression zone. Under cyclic flexural loading, high self-sensing repeatability and stability of FCR variation with strain were obtained for all the concrete beams, and concrete beam with 2.0 vol.% CNCFs demonstrated the optimum self-sensing capability for its highest strain sensitivity of 322.7. Consequently, by measuring FCR of concrete beams with CNCFs and replacing metallic steel reinforcement with nonconductive GFRP bars which have the benefits of avoiding short circuit or electric field disturbance inside self-sensing concrete, in-situ monitoring the strain and damage accumulation of concrete components can be achieved.

Chloride penetration in reinforced slag-based concrete beams under combined effects of loads and drying–wetting cycles

The use of concrete incorporating slag is necessary due to global environmental concerns, but the decrease in concrete durability caused by environments rich in chloride ions requires more advanced concrete mix designs, especially in coastal areas. The aim of this study was thus to assess the influence of slag addition on the transport of chloride ions in reinforced concrete (RC) beams under sustained bending moments, considering two conditions of environmental chlorine exposure: drying–wetting cycles and soaking. The results showed that the chloride diffusion coefficient (CDC) increased in tension zones and decreased in compression zones when the sustained bending load in the concrete beam was increased. However, it was also found that the addition of slag can significantly reduce the chloride diffusion depth and CDC for both environmental conditions, with a more significant effect under drying–wetting cycles. The chloride concentration on the surface of slag concrete in the compression zone was greater than that in the tension zone and greater than that in both the tension and compression zones of the ordinary concrete. A prediction model was established for describing the chloride penetration characteristics of concrete beams subjected to sustained bending moment. The proposed model is a reasonable approach for predicting chloride distribution in RC beams with slag addition subjected to bending moments.

Research on a safety evaluation system for railway-tunnel structures by fuzzy comprehensive evaluation theory

Long-term health detection of railway-tunnel is the development direction and trend of future railway tunnel research. Based on the actual engineering of a railway tunnel, this study developed a safety evaluation model for railway tunnel structures using a fuzzy comprehensive evaluation method and examined a health state evaluation method suitable for most railway tunnel structures. The results showed that the evaluation method comprehensively reflected the impact of various factors, which had strong practicality. The evaluation results were clear, accurate, and consistent with engineering practice. When using the safety factor index to study the stress of a railway tunnel structure, Midas/civil analysis showed that different levels of the surrounding rock structural vault in railway tunnels were in a tensile, control-bearing capacity state. When calculating safety factors, the range of a 60° central angle of a railway tunnel vault was calculated according to the tensile control-bearing capacity. Theoretical formulas of the range of the center angle φ0 of the vault tension zone were derived and then verified by experiments and numerical analysis.

Deformation of soft microbeam caused by wetting of droplet

Owing to the complexity of interaction on the solid–liquid interface, the wetting-induced deformation of micro-structure or soft matter is an open question. In this paper, a new model is developed to characterize the flexural deformation of microbeams with different supports induced by droplet wetting. Unlike the existing models, in this model it is no longer necessary to presuppose the distribution of the capillary tension and Laplace pressure on the wetted interface. The deflection of the microbeam due to wetting under different support conditions is solved analytically and compared with the results calculated by existing models. The results show that the capillary force that causes the microbeam to bend is not a self-equilibrium force system, but the assumption of the self-equilibrium traction in wetting-induced deformation is a good approximation. In addition, when the ratio of the size of the capillary tension zone to the wetted segment of the microbeam takes 0.55, the deflection curves calculated by the new model are agreement with those by the existing models.

Development and investigation of an innovative, light-weight, two-way spanning timber-concrete composite slab

Timber-concrete composite (TCC) slabs play an essential role in modern timber construction. Consisting of a timber member in the tension zone, a concrete layer in the compression zone and a shear connection between the two parts, TCC slabs feature a number of advantages that make them ideally suitable for use in both office and residential buildings. However, currently used TCC slab systems carry loads only in one direction. In the frame of a large research project in cooperation with the industry, an innovative, light-weight, two-way spanning timber-concrete composite slab using beech laminated veneer lumber with steel tubes as connectors was developed. This paper presents the main results of the research project. First, the structural behaviour of the connection is characterised and discussed based on extensive experimental and analytical analysis. Second, the load-bearing behaviour of the TCC slab investigated in uniaxial bending tests is presented. The uniaxial bending tests showed a remarkably ductile global load-bearing behaviour due to the ductile failure mode in the connectors. A developed analytical model can describe the observed load-bearing behaviour of the tested TCC members accurately. Finally, the biaxial load-bearing behaviour of the TCC slab is characterised and discussed based on a large-scale experiment that allowed to perform static and dynamic tests on the same specimen in different support conditions. A substantial increase in stiffness and fundamental frequency in biaxial versus uniaxial support conditions was observed and accurately modelled, showing the great potential of the novel TCC slab.

Investigations on atmospheric carbonation corrosion of concrete structure beam exposed to real marine-environment for 7 years

Concrete structure beam exposed to marine atmosphere environment easily suffers from carbonization corrosion and their true characterization is significant for their durability designs. In this work, concrete structure beam was exposed naturally for 7-years in a marine atmosphere environment of My Island (Qingdao, China) and their carbonization degree was characterized using the phenolphthalein (pH-value) and hydrochloric acid (HCl) titrations respectively to obtain their carbonation depth (Xd) and frontier (Xf). The results showed that the OPC concrete beam is only carbonized in its surface layer with a 3 mm carbonization depth while 6 mm Xf, both of which are smaller than the Xd (9 mm) and Xf (16 mm) of the concrete mixed with 50% slag replacement. The recommended carbonation amplification coefficients (Xf/Xd) of the OPC/slag-cement concretes are 2.1 and 1.8, respectively. The increased carbonization of the load-bearing concrete beam in the tension zone is greater than the reduction carbonization in the compression zone.

Experimental investigation of flexural buckling behaviour of self-compacting lightweight concrete-filled cold-formed built-up box section (CFBBS) columns

This paper presents an experimental investigation of the flexural buckling behaviour and resistance of innovative self-compacting lightweight concrete (LWSCC)-filled cold-formed built-up box section (CFBBS) columns. A series of sixteen LWSCC-filled CFBBS columns and four reference hollow columns formed by two nested asymmetric lipped channel sections using breakstem rivets at flanges with various member relative slendernesses ratios, concrete strengths and section sizes were tested under pin-ended boundary conditions. Material tests and initial global geometry imperfection measurements were carried out and reported in present study. The failure modes and deformation developments, lateral deflection distribution along the column specimens, flexural buckling resistance and load-end shortening relationship of the specimens were scrutinised and discussed concerning the effect of parameters and the associated coupling effects. Furthermore, a comprehensive strain analysis was conducted and reported based on the longitudinal and lateral strain developments at both compression and tension zones under flexure; it was found that the composite action abated as the member length increased. Finally, as there is no existing design codes for LWSCC-filled CFBBS columns, the experimental results were used to evaluate the applicability of relevant international codified provisions, including Eurocode (EC4), Australia/New Zealand Standard (AS/NZS 2327) and America Specification (AISC 360-16). It was found that AS/NZS 2327 yielded the most accurate and moderately scattered predictions while the predictions from EC4 were found to be the most scattered but with reasonable accuracy and those from AISC 360-16 were overly conservative, albeit the least scattered among these design codes.

ANALYTICAL MODEL OF THE T- STUB COMPONENT IN THE END-PLATE BOLTED CONNECTION OF THE BEAM TO THE COLUMN IN TENSION

End plated connections of metal structures are quite relevant and are usually used in office, commercial, and commercial-office buildings. It is very important to be able to diagnose the real general behavior of beam-to-column connections based on their geometric and mechanical properties. Therefore, the analysis of steel structures at the modern level requires a specialist to have a thorough understanding of their work, as well as the calculation provisions laid down in current design codes. In contrast to Eurocode 3 design codes, the current Ukrainian state building regulations do not contain clear instructions on the beam to column joint calculation and do not even give a clear definition of the concept of steel joint and steel connection. It should be noted that the beam to column connection is the most responsible area that requires special attention, as it significantly affects the design scheme of the structure, as well as its economic efficiency. By using the semi-rigid connection concept, weight savings of up to 20% can be achieved. In the presented article, a simplified mathematical model of the t-stub component of the tensile zone of the semi-rigid bolted connection of the beam to the column was developed using the component method. In the given solution of the connection in the tension zone, the following components were distinguished: the flange in bending, the end of the column in bending, and the bolts in tension. All these elements were modeled from two t- stub components connected through an end plate with the help of bolts. A design scheme for determining the stress-strain state was proposed. The analysis of the exhaustion of the bearing capacity of the t- stub component was performed according to three scenarios depending on the size of its individual elements (end plate thickness, bolt diameter). The obtained results will make it possible to determine the bearing capacity with possible variations of the transition to the limit state, as well as to estimate the deformations of the considered component of the connection. Keywords: end-plate connection, mathematical model, T-stub component, bolt connection.