Steel Reinforcement Ratio Research Articles

Nonlinear finite element models of reinforced concrete beams strengthened in bending with mechanically fastened aluminum alloy plates

This paper reports 3D nonlinear finite element (FE) models of reinforced concrete (RC) beams externally strengthened with mechanically fastened (MF) and externally bonded (EB) aluminum alloy (AA) plates. The measured and observed parameters of each specimen were obtained from an experiment conducted by the authors of this study. Each FE model adopted accurate material constitutive laws and appropriate element definitions to approximate the mechanical behavior observed during testing. A total of ten models were constructed based on the diameter, embedment depth, and arrangement of the expansion anchor bolt (EAB) as well as the presence or absence of epoxy. Results like the load-carrying capacity of the tested specimens as well as the failure modes like end-plate debonding (ED), local-plate debonding (LD), and plate rupture (PR) were accurately predicted. Additionally, Stress and strain contour plots were generated to investigate the FE models’ mechanical behaviors. Finally, a parametric study was conducted to illustrate the effects of the flexural steel reinforcement ratio and AA plate grades on the models’ structural response. It was concluded that the FE models could serve as a valid predictive platform for simulating the flexural behavior of RC beams strengthened with MF and EB AA plates.

Experimental and numerical investigation on the effectiveness of NSM and side-NSM CFRP bars for strengthening continuous two-span RC beams

This paper aims to present and analyze the results of an ongoing research project on the use of NSM and side-NSM-FRP composites for the purpose of increasing the load-carrying capacity of two-pan continuous RC beams. This research study comprises two parts; an experimental part and a finite element (FE) part. First, three large-scale two-span beams were statically investigated; one control beam and two other beams initially strengthened in bending with two 6 mm diameter CFRP bars. Second, a three dimensional (3D) FE model was developed, using the computer software ABAQUS, in order to predict the flexural performance of the tested beams and to investigate the influence of the models applied to the CFRP-resin-concrete interfaces. The results obtained indicated that the side-NSM-CFRP bars system is a convenient alternative to the conventional one for strengthening continuous beams. For some strengthening configurations, the side-NSM technique proved to be more efficient than the NSM technique, particularly when the CFRP bars were applied solely in the hogging region or the sagging regions. The moment redistribution of strengthened beams was negatively affected when the steel reinforcement ratio in the hogging region was increased. Nevertheless, the moment redistribution degree was significantly affected by the position and arrangement of the CFRP bars. The 3D-FE analysis developed with the cohesive zone model can capture the main aspects observed from the experiments.

The structural behaviours of steel reinforced geopolymer concrete beams: An experimental and numerical investigation

The environmental impact of traditional Ordinary Portland Cement (OPC) concrete is a significant problem that requires urgent solutions in the construction industry. The development of geopolymer concrete is one of the most significant breakthroughs in the process of replacing OPC concrete. Through comprehensive experimental and numerical analyses, this study investigates the structural behaviours of large-scale steel reinforced geopolymer concrete beams (GCBs) made from low-calcium fly ash and ground granulated blast furnace slag (GGBFS). Firstly, small-scale experiments were carried out to investigate the effects of water/binder and activator/binder ratios on the mechanical properties of geopolymer concrete (e.g. elastic modulus, compressive strength, direct tensile strength). The experimental results show that the mechanical properties of geopolymer concrete increases with increasing the activator/binder ratio and decreasing the water/binder ratio. Secondly, three groups of GCBs with different steel reinforcement ratios (D1-0.41%, D2-0.75%, and D3-1.5%) were made and four-point bending tests were conducted. The same mix proportion (water/binder of 0.45 and activator/binder of 0.08) with the compressive strength of 39.1 MPa, elastic modulus of 32.0 GPa, and the direct tensile strength of 3.06 MPa, was used for the three groups. The obtained moment–curvature results, which consists of three distinct stages (linear elastic, tension cracking of GCBs, and steel yielding), show that the three groups (D1-D3) behave in a ductile manner. Moreover, the moment capacity of GCBs increases when the steel reinforcement ratio increases (D1-21.5 kNm, D2-44.2 kNm and D3-83.6 kNm). Finally, nonlinear, three-dimensional finite element (FE) analysis based on the damage plasticity constitutive law was developed to capture and validate the structural behaviour of GCBs from the experiments. Numerical results indicate that the developed FE models accurately capture the structural behaviours (moment–curvature and cracking behaviour) of GCBs. The discrepancies between the numerical and experimental moment–curvature results are from 1 to 5% for the tensional cracking and yielding points. Therefore, the developed FE models can be used as an effective tool for the further development and design of geopolymer concrete structures.

Structural performance of reinforced self-compacting concrete columns produced with palm oil fuel ash

Palm oil fuel ash (POFA) is an agricultural waste produced from the palm oil industries and disposes off into an open ground without any reprocessing or profitable return, has been established to enrich concrete durability as well as mechanical properties when used to replace cement. However the POFA used to partially substitute cement in self-compacting concrete (SCC) production were done on material properties by fabricating standard specimens such as cylinders, prisms and cubes. Moreover, the utilization of POFA to partially substitute cement to cast reinforced concrete structural members is not common compared to fly ash and ground granulated blast furnace slag. This study therefore focuses on structural performance of reinforced self-compacting concrete columns produced with palm oil fuel ash. Two mixes of SCC containing 0% and 15% of POFA were prepared to fabricate the columns. The main variables considered were percentage of POFA content, percentage of steel reinforcement ratio (2% and 3%) and thickness of concrete cover (25 mm and 35 mm). Eight columns were fabricated altogether and tested under axial compression load up to failure. The results of the test revealed that the ultimate axial capacity of reinforced SCC columns produced with POFA is higher than the columns produced without POFA by approximately 2.6% and 2.2% for 25 mm and 35 mm concrete covers, and 2.9% and 2.5% for 2% and 3% steel reinforcement ratios. It is also observed that the load-deflection pattern of reinforced SCC columns produced with and without POFA follow similar trends. However, columns produced with POFA showed slightly lower stiffness than the columns produced without POFA.

Behavior of Reinforced Concrete Plates under Pure Torsion

The behavior of reinforced concrete members under torsional loading has interested many researchers during the last decades. These researches focused mainly on the response of reinforced concrete beams at different reinforcement conditions and the size effects. On the other hand, the behavior of concrete plates or slabs has not been investigated clearly under pure and/or combined torsional loading. In the present study, nine reinforced concrete plates were prepared and tested under pure torsion. Effect of steel reinforcement ratio and size change was studied and they have a great effect on the plated strength, capacity, stiffness and ductility. As stated by torsion theories of reinforced concrete beams, the torsional strength of slabs was upgraded also with increasing in cross section and transverse reinforcement ratio.

3D concrete printing of permanent formwork for concrete column construction

This study investigated 3D concrete printing of permanent formwork for concrete column construction. The effect of different hydroxypropyl methyl cellulose (HPMC) contents (0, 0.0003 and 0.0006 by mass of binder) and the water-to-binder (W/B) ratios (0.27, 0.29 and 0.31) on the rheological properties, structural build-up and mechanical performance were studied using several mixtures for manufacture of the permanent formworks. The results showed that the mixture with the HPMC = 0.0006 and the W/B = 0.27 showed the maximum static yield stress, largest thixotropy and maximum green strength, and thereby selected as the optimum mixture. The plastic failure of the optimum mixture was also predicted using a thixotropy model and was compared with the experimental results. Subsequently, three concrete columns with different longitudinal steel reinforcement ratios (0.0%, 1.9% and 2.5%) were constructed using the printed concrete as the permanent formwork and tested in compression. Good bonding was observed at the interface of the cast-in-place concrete and the printed concrete permanent formwork. In addition, it was observed that the initial stiffness, the maximum bearing capacity and the corresponding longitudinal displacement of the concrete columns increased, as the longitudinal reinforcement ratio increased. The counterpart concrete columns using the conventional formworks were also constructed and tested for comparison. In comparison, the concrete columns made using the printed concrete as the permanent formwork obtained a higher stiffness and bearing capacity than the counterpart conventional concrete columns. The reasons for the differences are explained.

Application of ABAQUS on the Research of the Thermal Field of SRC Columns

According to the basic principles of heat transfer, the thermal field of SRC columns under fire is analyzed by finite element analysis software ABAQUS and the calculated results agree well with experimental data at home and abroad. On this base, the influence of parameters of sectional dimensions, length-to-width ratio of the section, steel ratio and reinforcement ratio to the distributing circumstance of thermal field of SRC columns are analyzed. The results show that parameters of sectional dimensions and length-to-width ratio are the most important factors affecting the distributing circumstance of thermal field of SRC columns. The larger the parameters of sectional dimensions, the lower the component temperature. The greater the length-to-width ratio, the greater the component temperature is. Steel ratio and reinforcement ratio have almost no effect on the distributing circumstance of thermal field of SRC columns. The achievements make it possible to study further the mechanical performance of SRC columns at high temperature.

Investigate the Structural Response of Ultra High Performance Concrete Column under the High Explosion

Most of the structures that are damaged by an explosion are not initially designed to resist this kind of load. In the overall structure of any building, columns play an important role to prevent the collapse of frame structure under blast impact. Hence, the main concept in the blast resistance design of the structure is to improve the blast load capacity of the column. In this study, dynamic analysis and numerical model of Ultra High Performance Concrete (UHPC) column under high explosive load, is presented. Based on the Johnson Holmquist 2 damage model and the subroutine in the ABAQUS platform, a total of twenty UHPC model of the column were calculated. The objective of the article is to investigate the structural response of the UHPC column and locate the most vulnerable scenarios to propose necessary recommendations for the UHPC column in the blast loading resistance design. The input parameters, including the effect of various shapes of cross-section, scaled distance, steel reinforcement ratio, and cross-section area, are analyzed to clarify the dynamic behavior of the UHPC column subjected to blast loading. Details of the numerical data, and the discussion on the important obtained results, are also provided in this paper.

Lateral cyclic response sensitivity of rectangular bridge piers confined with UHPFRC tube using fractional factorial design

Through the use of ultra-high performance fiber reinforced concrete (UHPFRC) tubes in an RC bridge pier, the pier can substantially reduce seismic damages during earthquakes compared to the conventional RC piers. The seismic behavior of such a novel bridge pier is affected by various design factors. This study aims at identifying the significant levels of each main factor and their interactions which affect the cyclic response of UHPFRC tube-confined pier. A fractional factorial design methodology is used to statistically estimate the effects of different main factors and their interactions. 3D finite element models of the UHPFRC tube-confined columns are first generated and validated by using experimental results. Then, a sensitivity study is conducted considering ten potential material and geometry-related factors. Five response variables, i.e. the initial stiffness, load-carrying capacity, residual drift, hysteretic energy dissipation, and equivalent viscous damping, for the UHPFRC tube-confined column are examined. From the parametric study, the significant factors including the main factors and their interactions are determined for each response variable. According to the sensitivity analysis results, predictive equations are proposed to predict the response quantities for other UHPFRC tube-confined columns with the same column cross-section through regression analysis. Results demonstrate that the longitudinal steel reinforcement ratio, axial load ratio, and aspect ratio have large effects (with total contributions greater than 40%) on all the response variables.

Numerical investigation of the parameters influencing the behavior of dapped end prefabricated concrete purlins with and without CFRP strengthening

Dapped end prefabricated concrete purlins (PCPs) suffer from shear damages due to coating, snow, wind load and also their dead loads. In this present study, a series of numerical modelling is performed with the aid of finite element program ABAQUS in order to investigate this behavior of PCPs through parametric study. In addition to the mechanical properties of the PCPs, the strengthening of the PCPs with the help of carbon fiber reinforced polymers (CFRP) is considered as a parameter in the models. Pursuant to this aim, longitudinal steel reinforcement ratio, shear friction reinforcement ratio, bending reinforcement ratio, suspension reinforcement ratio, concrete and steel mechanical properties, pre-stressing level, CFRP ply orientation, the number of CFRP plies and material properties of CFRP composite were selected as the parameters. First of all, numerical models were verified using experimental test data of three PCP test specimens and five CFRP coupon tests. Later, a total of 50 different numerical models was created to investigate the behavior of PCPs thoroughly. Vertical load- displacements curves are compared and explained in detail. The result of the parametric study revealed that the effects of the parameters related to reinforced concrete except longitudinal reinforcement and material properties of concrete are very limited when compared to the effects of the parameters related to CFRP. The effect of FRP ply orientation is the most effective parameter that increases significantly the shear capacity of PCPs. More importantly is the general FRP layout is proposed to delay or prevent shear cracks for the beams and the proposed layout is proved through numerical analyses. [±45°] fiber orientation is recommended to use to prevent shear damage.

Flexural strengthening of over-reinforced concrete beams with highly ductile fiber-reinforced concrete layer

This study investigates the effectiveness of highly ductile fiber-reinforced concrete (HDC), which is characterized by its high ultimate compressive strain ability, in improving the failure mode and deformational characteristics of over-reinforced concrete beams. The flexural behavior of over-reinforced concrete beams strengthened with HDC was experimentally investigated. The variables included the tensile longitudinal steel reinforcement ratio, thickness of the layer, strengthening materials, and strengthening methods. The crack pattern, failure mode, load–deflection responses, flexural capacity, ductility, and strain were investigated. The experimental results indicated that applying HDC to strengthen the compression zone of an over-reinforced concrete beam is a highly effective method to change its brittle failure and improve the ductility. HDC-strengthened beams showed an increase in flexural capacity and deformation compared to normal concrete-strengthened beams with equal strengthening thickness. A better deformation capacity can be achieved by using a larger thickness of the strengthening layer, ensuring the coordination between the strengthening layer and the existing beam. The effectiveness of HDC in strengthening over-reinforced concrete beams was improved as the tensile longitudinal steel reinforcement ratio increased. A simplified calculation method for the flexural capacity of HDC-strengthened beams was proposed, which is in good agreement with the experimental results. The compression zone relative depth for the balanced failure could be notably improved by applying a larger thickness to strengthen the compression zone of over-reinforced concrete beams than the critical thickness of the HDC layer, which can be calculated by the proposed approach.

Numerical Study on Flexural Behavior of Concrete Beams Strengthened with Fiber Reinforced Cementitious Matrix Considering Different Concrete Compressive Strength and Steel Reinforcement Ratio

Concrete structures retrofitted with fiber reinforced cementitious matrix (FRCM) have become widespread due to their mechanical and durability performances. However, the behavior of FRCM -strengthened RC members under service loads is still a concern, and more efforts need to be done. In this study, a nonlinear three-dimensional finite element (FE) model has been developed to study the performance of reinforced concrete (RC) beams strengthened by (FRCM). The model was validated against the experimental results gathered from six beams tested under three-bending points. Consequently, the primary numerically studied parameters were longitudinal steel reinforcement ratio and concrete compressive strength. A cohesive damage parameters were investigated to represent the experimental results. Also, the theoretical flexural capacity of strengthened beams based on ACI-549 code was evaluated based on the numerical method results. As a conclusion, the numerical results are in a very good agreement with the experimental ones regarding yielding load, ultimate load, and failure mode. In addition, the developed models from parametric studies concluded the insignificant effect of concrete compressive strength on increasing the ultimate capacity of strengthened beam. However, the steel reinforcement ratio has a major impact on enhancing the ultimate capacity of strengthened beams.

A Comparative Study on Behavior of RC Columns Strengthened by CFRP and Steel Jacket

This paper studies the behavior of axially loaded RC columns which are confined with carbon fiber reinforced polymers’ sheet (CFRP) and steel jackets (SJ). The study is based on twelve axially loaded RC columns tested up to failure. It is divided into three schemes based on its strengthening type; each scheme has four columns. The main parameters in this study were the compressive strength of the concrete and steel reinforcement ratio. Furthermore, the results of the experimental test showed a substantial enhancement in the column's load-carrying capacity. When compared to the original columns, the CFRP sheet had a significant effect on improving the ductility of the column by increasing the axial deformation by about 59.2 to 95.7%. On the other hand, the SJ contributed mostly to the column load-carrying capacity, which increased the capacity of RC concrete from 75 to 107%; because of its composite action comparing with the CFRP sheet action in which unidirectional lateral confinement is provided. Both methods produced completely different failure modes. The columns strengthened with CFRP sheet failed by rupture occurring in the sheet fibers. The strengthened with SJ failed due to the buckling that occurred in the steel angles due to the direct contact with the head of the column, and crushing in the concrete has occurred.

Self-compacting concrete beams reinforced with steel fiber under flexural loads: A ductility index evaluation

Abstract Although the ductility index of the reinforced concrete element has been the subject of many research objectives and critical analysis recently, scare consideration is carried out to measure the ductility of reinforced self-compacting concrete (SCC) enhanced with steel fiber. Hence, the current study aims to evaluate the ductility, in terms of energy absorption, of reinforced steel fibrous self-compacting concrete beams subjected to experimental flexural force. Twelve reinforced SCC beams experimented under flexural loads including pair groups of six beams (with and without steel fibers). Minimum and maximum steel ratio ( ρ min and ρ max ) and three grades of concrete (G20, G50, and G60) are used in this study. Load-displacement curves ( P - Δ ) are used as a tool to measure the ductility Energy index ( μ E ) of the tested SCC beams using Spadea et al (1997) technique. The result shows that the flexural stiffness of the fibrous SCC beam specimens is improved to overcome beam deformation and consequently constrained cracking. The results reveal also that the increase of fibrous material to SCC is extremely efficient. In terms of increasing energy dissipation, flexural capacity, and ductility index ( μ E ). Besides, the flexural strength grows with increasing steel fiber percentage, steel reinforcement ratio, and concrete compressive strength.

Experimental and analytical investigation on structural behavior of two-layer fiber-reinforced concrete beams reinforced with steel and GFRP rebars

The combination of plain concrete and fiber-reinforced concrete in beams in the form of two-layer composite members can be an efficient solution to improve the flexural behavior, reach the optimum distribution of steel fibers, and reduce the cost of these structural elements. On the other hand, the glass fiber reinforced polymer (GFRP) rebar can serve as a proper alternative for the steel rebar in reinforced concrete beams considering its superior strength to weight ratio compared with the steel rebar. The objective of this research was to evaluate the structural performance of two-layer fiber-reinforced concrete beams with glass fiber-reinforced polymer (GFRP) and steel rebars under quasi-static loads. For this purpose, three groups of concrete beams reinforced with GFRP rebars and four groups of concrete beams reinforced with steel rebars were fabricated with one- and two-layer sections containing different volume fractions of steel fibers (Vf = 0, 0.75, and 1.5%), without using shear reinforcement. The longitudinal reinforcement ratios were 0.37 and 0.73% for GFRP and 1.05 and 2.1% for steel rebars, and the concrete compressive strengths were 33 and 64 MPa. The fabricated beams were then tested under three-point bending. The results of the layered concrete beams showed that adding fibers to the compression zone of the section led to a higher ductility in both GFRP rebar- and steel rebar-reinforced beams, while adding fibers to the tensile zone led to a higher ultimate flexural strength. Furthermore, an increase in the ratio of GFRP and steel reinforcement together with a greater concrete compressive strength in the layered beams enhanced their flexural performance in terms of load-carrying capacity, flexural stiffness, and ductility; however, replacing steel rebars with GFRP ones led to a decrease in these parameters. Finally, the flexural response of the layered concrete beams reinforced with GFRP and steel rebars was predicted via sectional analysis and using empirical equations developed for the mechanical properties of the constituent materials. The analytical results indicated a good agreement between the proposed model and the experimental results, to the extent that the model was able to properly predict the flexural behavior of the layered concrete beams in terms of the ultimate load-carrying capacity and mid-span deflection.

Deformation-based performance index of corroded reinforced concrete beams

In order to implement the life-cycle oriented performance-based seismic design of reinforced concrete (RC) structures, quantification of seismic performance indexes for corroded RC members is necessary. Firstly, the material strain-based criteria to classify damage limit states for RC members were proposed. Numerical analysis was conducted with the aid of the software ABAQUS to investigate the deformation behaviour of RC beams. Corrosion ratio of steel reinforcement, shear span ratio and longitudinal reinforcement ratio were considered as the main analytical parameters. It is found that for RC beams with corrosion ratio not exceeding 7.5%, the corrosion ratio of steel reinforcement has little effect on the deformation behaviour of RC beams. For RC beams with corrosion ratio lager than 7.5%, the deformation capacity is significantly affected by the reinforcement corrosion ratio. Based on numerical simulation results, expressions for estimating deformations of corroded RC beams at yield and ultimate limit states were derived, respectively. The deformation limits corresponding to the individual damage limit state of corroded RC beams were proposed. The research results can be utilized for life-cycle oriented seismic performance evaluation and design of RC structures.

An experimental study on axial behavior of CFRP-strengthened RC rectangular columns with variable slenderness ratio

In the construction industry, carbon fiber-reinforced polymer (CFRP) composites are widely used for retrofitting and rehabilitation of reinforced concrete (RC) rectangular columns to enrich the service life of structures. The CFRP-confined RC rectangular column with a variable slenderness ratio has limited design provisions in available design codes. The aim of the current experimental work is to explore the efficacy of slenderness ratio on the axial performance of CFRP composite-confined rectangular columns having a constant cross-sectional area and steel reinforcement ratio. The experimental results clearly demonstrated that the yield strength, ultimate strength, and ductility of the RC column after CFRP confinement are significantly influenced by the variation in the slenderness ratio. The response of CFRP wrap, transverse and longitudinal reinforcements in the strengthening process of the RC rectangular column also remarkably varied for different slenderness ratios.

A NUMERICAL STUDY ON SEISMIC PERFORMANCE EVALUATION OF RC RECTANGULAR COLUMNS STRENGTHENED WITH CFRP SHEETS

External confinement of reinforced concrete columns using fiber-reinforced polymer (FRP) sheets can significantly enhance their seismic behavior. This research presents a numerical investigation to evaluate the seismic performance of RC rectangular columns with limited cross-sections' aspect ratios (1, 1.5, and 2) strengthened with a fully wrapped CFRP jacket under constant axial and pushover lateral loads. Therefore, a three-dimensional finite element model was implemented via ABAQUS software, which has been adopted in this study, where the proposed model showed a reliable agreement with the previous experimental work. The studied parameters are: longitudinal steel reinforcement ratio, CFRP confinement ratio, and axial load/capacity ratio for each cross-section aspect ratio. The obtained numerical results have proved that the external wrapping of RC rectangular columns with CFRP sheets has effectively increased drift capacity ratios for cross-sections aspect ratios 1, 1.5, and 2. Moreover, the strengthening of RC rectangular columns using external CFRP wrapping increases the nominal shear and flexural strengths of the strengthened columns. Also, the effect of increasing the longitudinal steel reinforcement ratio can significantly decrease the ultimate lateral displacement and drift capacity ratios. Besides, with the increase of the axial load/capacity ratios, the drift capacity ratios significantly decrease for the strengthened RC rectangular columns.

Development of pressure-impulse models and residual capacity assessment of RC columns using high fidelity Arbitrary Lagrangian-Eulerian simulation

Pressure-Impulse (P-I) models as graphical representations are frequently adopted to evaluate damage of structures subjected to extreme loads. The main objectives of this research is to derive analytical formulas to propose pressure (P0) and impulsive (I0) asymptotes of RC columns at different levels of damages, and to develop P-I models and empirical equations of RC columns for prediction and assessment of blast induced damages using an advanced numerical modeling approach. An innovative technique to predict the residual capacity of RC columns when subjected to detonation events is essential to measure the column axial capacity after blast loads. This study can offer a methodology for a reliable, simple and accurate dynamic analysis to study the residual capacity of columns under blast detonation. Available literature mainly focused on the simulation of explosion loads by using simplified pressure time histories to develop P-I curves and rarely simulated the actual explosive. Therefore, there is a gap in the literature concerning general relation between blast damage of columns with different explosive loading conditions for a reliable and quick evaluation of column behavior subjected to blast loading. In this paper, the Arbitrary Lagrangian Eulerian (ALE) technique is implemented to simulate high fidelity blast pressure propagations. The numerical model is calibrated and validated by comparing the results from blast field tests performed by other researchers. To develop the designated P-I curves, damage assessment criteria are used based on the residual capacity of column. Intensive investigations are implemented to assess the effect of column dimension, concrete and steel properties, reinforcement ratio and axial load index on the P-I diagram of RC columns. The produced P-I models can be applied by designers to predict the damage of new columns and to assess existing columns subjected to different blast load conditions.

Experimental Study on Interfacial Shear Performance of RC Beams Added to Existing RC Columns

The primary objectives of this study were to experimentally investigate the shear characteristicsof the interface between an existing RC column and a reinforced concrete (RC) beam added to the existing RC column, and to propose a formula for estimating the shear capacity of the beam-column interface. The major test variables consisted of concrete strength, added steel reinforcement ratio and shear span to depth ratio. Failure characteristics, displacements at the loading point, slips of the beam-column interface, and shear capacities of the beam-column interface were analyzed. Test results indicate that both the shear capacity of the beam-column interface and the corresponding interfacial slip increased with a decrease in shear span to depth ratio. In addition, as concrete strength grew, the shear capacity of the beam-column interface increased, but the interfacial slip corresponding to the interfacial shear capacity remained almost unchanged. Moreover, both the shear capacity of the beam-column interface and the corresponding interfacial slip increased with an increase in the longitudinal steel reinforcement ratio of the added RC beam. A formula for predicting the shear capacity of the beam-column interface was developed. The test results validate the proposed formula and provide important guidance for the design of the RC beam added to the existing RC column.