Displacement Ductility Ratio Research Articles

Constant-ductility inelastic displacement ratio spectra for design of superstructures in seismically isolated buildings

Constant-ductility inelastic displacement ratio (Cμ) spectra can be utilized for the estimation of peak inelastic structural displacements in the seismic design procedure. Currently, suitable analytical estimates of Cμ are lacking for base-isolated buildings with inelastic behavior of superstructures in a beyond design basis earthquake. This paper attempts to fill this research gap and hence conducts parametric studies on the Cμ spectra of base-isolated inelastic superstructures with lead-rubber bearings (LRBs). For that purpose, the inelastic model and equations of motion, boundary conditions of the analytical formulation of Cμ, and controlling parameters for the two-degree-of-freedom (2DF) superstructure-isolator system with LRBs are presented first. Subsequently, by analyzing the parameterized 2DF systems using an ensemble of strong earthquake records representative of a site with stiff soil conditions, the influence of controlling parameters, namely, displacement ductility ratios, superstructure periods, post-yielding stiffness ratios of superstructures, mass ratios, isolation periods and normalized isolator strength, on the mean and dispersion of Cμ are discussed, and the boundary conditions of Cμ are validated based on the calculated data. Comparisons of how the controlling parameters influence the Cμ and earlier investigated CR (i.e. constant-strength inelastic displacement ratio) spectra are also presented. Lastly, a predicting equation with reasonable accuracy is proposed for the mean Cμ using the nonlinear multivariable regression analysis method. The outcome of this study allows the application of displacement-based design via inelastic displacement ratio for new base-isolated structures under beyond design basis earthquakes.

Flexural Response of Functionally Graded Rubberized Concrete Beams.

Recycling rubber and/or steel fiber components of waste tires in construction applications is a venue for maximizing the recycling rate of these items. Additionally, it supports the move towards producing sustainable construction materials and conserving natural resources. Previous research explored the viability of employing recycled waste rubber particles as an alternative for natural aggregate. Despite the adverse effect of rubber on the mechanical properties of concrete (e.g., lower compressive strength), it produces several advantages, including excellent dynamic and ductility properties, which can be utilized in structural members critical to dynamic loads, e.g., blasts, earthquakes, and impacts. In an effort to expand the adoption of waste rubber in concrete beams and to eliminate key concerns associated with the degradation of their flexural behavior, the functionally graded (FG) beams concept was utilized. The present investigation comprised the testing of five beams using a four-point bending configuration. Plain concrete, rubberized concrete (RuC), and steel-fiber reinforced rubberized concrete (SFRRuC) beams were cast along with FG beams arranged in two layers. The top layer of the FG beams comprised plain concrete, while the bottom layer consisted of RuC or SFRRuC. Experimental findings indicated that the flexural behavior of the FG beam with layers of SFRRuC and plain concrete exceeded the flexural strength, displacement ductility ratio, and toughness performances of the plain concrete beam by 9.9%, 12.9%, and 24.4%, respectively. The moment-curvature relationship was also predicted for the tested beam and showed an excellent match with the experimentally measured relationship.

Experimental and numerical investigation of hysteretic earthquake behavior of masonry infilled RC frames with opening strengthened by adding rebar-reinforced stucco

Adding a reinforced stucco layer to the masonry infill walls is a preferred method for strengthening RC frame system structures with an easy-to-apply method that does not require a long time, is economical, and does not require detailed and extensive workmanship. However, no research has been discovered as a result of the extensive literature review that investigates the effects of masonry-infilled RC frames strengthened with a reinforced stucco layer on the seismic performance of openings that must be due to architectural requirements such as doors, windows, installations, and similar ventilation systems. As a result, an experimental study was planned to investigate the effects of the dimensions and location of the opening in the masonry infill walls on the performance of the strengthening method with the reinforced stucco layer. The applied strengthening method increased the ultimate load capacity, initial stiffness, and energy dissipation capacity values of reinforced concrete frames with masonry infill walls by 83%, 226%, and 62%, respectively, but resulted in a 38% decrease in displacement-ductility ratios. The study found that the openings in the masonry infill walls harm the performance of the strengthening technique by adding a rebar-reinforced stucco layer and decreasing the success level. When the opening size increased, and the opening was located at the corner of the masonry wall, the performance of the applied strengthening technique was negatively affected and decreased. Furthermore, nonlinear numerical analyses of the experiments conducted as part of the study were performed using ABAQUS finite element software. The numerical analysis results were compared to the experimental results. It has been determined whether numerical analysis models are compatible with experimental results.

Experimental Study on Hysteretic Performance of Steel Moment Connection with Buckling-Restrained Dog-Bone Beam Sections

Steel beam–column connections with dog-bone beam sections have gained significant attention and have been extensively applied. This is attributed to their ability to effectively centralize and integrate plastic hinges, thereby diverting potential damage away from the beam ends during earthquake events. In order to achieve the enhancement of the ductility and energy dissipation of connections by inhibiting local buckling during an earthquake event, a novel steel moment connection with buckling-restrained dog-bone beam sections was proposed in this paper. There were three types of proposed connections according to the different arrangements of restrained steel plates, including arranging the restrained plates only on the flanges, only on the web, and on both the flanges and webs of the dog-bone beam sections. In this study, three specimens with buckling-restrained dog-bone beam sections and one control specimen with a dog-bone beam section were tested under cyclic loading. The failure modes, hysteretic curves, skeleton curves, stiffness degradation ductilities, displacement ductility ratios, and energy dissipation capacities of the specimens were analyzed based on the experimental results to evaluate the seismic behavior of the proposed connections. The results indicated that the local buckling of the proposed connections was significantly reduced compared with the traditional connection with a dog-bone beam section under the condition of keeping the plastic hinges away from the beam–column connection core. The arrangement of the restrained plates in the dog-bone beam section had little effect on the bearing capacity and the initial stiffness, with errors all being within 6%. It is worth mentioning that the connection with restrained plates only on the flanges in the dog-bone beam sections showed a more obvious improvement in the deformation capacity and energy dissipation capacity of the connection, which increased by 21% and 16%, respectively. Additionally, high-quality welding between the beam and column, smooth cutting shapes on the weakened flanges, and the high-quality drilling of long slots at the fixed point in the restrained plates and the dog-bone beam sections should be guaranteed to improve the hysteretic stabilities of the proposed connections.

WITHDRAWN: Out-of-plane push-over testing of masonry wall reinforced with prestressed wedges

Masonry partition walls are vulnerable to lateral loads, including seismic, wind, and concentrated push loads. Various strengthening metal fittings have been proposed to improve lateral load resistance, particularly against seismic loads. This study introduces the use of prestressed wedges as a novel reinforcement method for masonry partition walls to enhance lateral load resistance. The resistance of the masonry partition wall against lateral-concentrated push loads was assessed using an out-of-plane push-over test on specimens sized 2300 × 2410 × 190 mm3. The presence or absence of wedges and wedge spacing were set as variables. The push-over test results showed that both the unreinforced specimen and the specimen reinforced with 300 mm spaced wedges toppled, while the specimen reinforced with 100 mm spaced wedges remained upright. Peak loads were measured to be 0.74, 29.77, and 5.88 kN for unreinforced specimens and specimens reinforced with 100 mm and 300 mm spaced wedges, respectively. Notably, a tighter reinforcement spacing yielded a similar strength, as expected, which was attributed to the increased friction force between the masonry wall and steel frame. The W-series specimens exhibited a trend comparable to that of the displacement ductility ratio. Overall, the findings validate that prestressed wedges improve the out-of-plane strength of masonry partition walls.

Experimental Study on Seismic Performance of Partially Corroded Squat RC Shear Walls in Coastal Environment

In coastal environments, squat reinforced concrete (RC) shear walls are susceptible to local accumulation of moisture and chloride salts, causing local corrosion in the shear walls, which in turn affects their seismic performance. Four squat RC shear wall specimens were designed considering the corrosion locations and the heights of the corroded area. The seismic performance of partially corroded squat RC shear wall specimens was analyzed through a quasi-static test. The results show that as the height of the corroded area increases from 15% to 25% of the total height, the area of the hysteresis loop of the shear walls obviously decreases. As the height of the corroded area increases from 0 to 15% and 25% of the total height, the peak and ultimate displacements of shear walls are, respectively, reduced by 6.7% and 19.2% in the positive loading direction, and are, respectively, reduced by 22.3% and 18.3% in the negative loading direction. Compared with the unilateral corroded shear wall, the area of the hysteresis loop and the stiffness of the bilateral corroded shear wall remain approximately unchanged, and the peak and ultimate displacements, the shear strain, and the ratio of shear deformation to horizontal displacement are reduced. Compared with the uncorroded shear wall, the hysteresis loop of the unilateral corroded shear wall is plump, the displacement ductility ratio and the plastic rotation angle are both increased, and the stiffness degradation is relatively slow.

Retrofitting of squat RC column by using TRM strip under axial load

This study investigates the retrofitting of reinforced concrete columns with TRM strips. Seventeen test specimens were produced, and one was chosen as a reference test specimen. Damaged by loading up to 50% of their maximum axial load-carrying capacity test specimens were retrofitted with two different carbon textiles. In addition to the textile type, TRM strip width, strip spacing, and the use of anchors were determined as experimental variables. Maximum bearing capacity, displacement at bearing capacity, initial stiffness, displacement ductility ratio, and energy consumption capacity were calculated using the axial load-displacement graphs obtained from the experimental study. Depending on the obtained results, the effects of experimental variables on the behavior of damaged reinforced concrete columns were interpreted and compared. It has been determined that the retrofitting method presents very successful results. It has been observed that the fan-type anchor, which is rarely used in literature studies, significantly increases the maximum bearing capacity and energy consumption capacity values of test specimens. Finally, the experimental results were compared with those obtained from the numerical models created by the ABAQUS finite element software.

Experimental study on flexural behavior of T‐shaped reinforced concrete laminated beams with defects

AbstractTo study the influence of the defects on the flexural behavior of laminated T‐beams, full‐scale beam tests of three reinforced concrete laminated T‐beams with incomplete bonding and one non‐defective reinforced concrete laminated T‐beam were conducted under monotonic loading. The results showed that the failure modes and crack patterns of the defective beams were similar to those of beams without defects. However, horizontal cracks appeared in these defects. Although the peak loads of the four specimens were relatively close, the difference in the maximum deflection was distinct. The deflection span ratio of each specimen exceeded 1/17, and the displacement ductility ratio exceeded 15. The results indicate that internal defects have only a slight influence on the flexural capacity of laminated beams but significantly influence their ductility.

Seismic performance of precast lightweight aggregate concrete shear walls with supplementary V-ties

This study examined the flexural behavior of a precast lightweight aggregate concrete shear wall (PLCSW). To minimize crosstie arrangement congestion in the boundary elements and improve ductility, the conventional reinforcing crosstie was replaced with the supplementary V-tie developed by Yang et al. Additionally, a bolting technique, which combines steel plates, bolts, and nuts, was applied to the PLCSW wall-to-base connection. The behavior of these specimens was compared with the flexural behavior of conventional precast concrete shear walls (PCSW) connected via the spliced sleeve technique. Eight PCSW specimens with different crossties (supplementary V-ties or conventional reinforcing crossties) were prepared and wall-to-base connection techniques (bolting or spliced sleeve connections) applied. All specimens were tested under constant axial load and cyclic lateral loads. The ductility performance of PCSW was verified through a comparative analysis of the displacement ductility ratio and work damage index between the PCSW with supplementary V-ties and those with conventional reinforcing crossties. The ductility performance of PCSW utilizing supplementary V-ties and the bolting technique exhibited superior ductile performance resulting in a high work damage index, which was 1.22 times higher than that of the PCSW with conventional reinforcing crossties. Meanwhile, even though the shear wall specimens connected via the spliced sleeve technique were produced with normal-weight aggregate concrete, their work damage indices were slightly lower than those of the specimens utilizing conventional reinforcing crossties and the bolting technique. Consequently, the PCSWs with the spliced sleeve did not satisfy the seismic connection performance requirements specified in NEHRP, whereas the precast sand-lightweight aggregate concrete shear walls with supplementary V-ties utilizing the bolting technique satisfied the requirements. Therefore, the ductility and seismic connection performances of PCSWs with a complex detail arrangement of the boundary element can be effectively improved by using a supplementary V-tie and applying bolting techniques.

Flexural behavior of precast lightweight aggregate concrete insulation panels

This study examined the effect of different panel-to-base connection techniques on the flexural behavior of precast lightweight aggregate concrete (PLC) panels with an embedded honeycomb cardboard for lighter weight and better insulation performance. Eight full-size PLC insulation panels were prepared with test parameters including panel-to-base connection techniques, the compressive strength of concrete (fc′), and continuity of span. All panel specimens were tested under symmetrical two-point top loadings in each span. The test results revealed that the flexural design process specified in the code American Concrete Institute 318-19 commonly underestimated the flexural cracking and moment capacity of the PLC specimens. The PLC insulation panel specimens with an fc′ exceeding 13 MPa could be classified into grade 1 as specified in the code KS F 4736, indicating a good flexural resistance. For conservative flexural design of PLC insulation panels, the use of the conventional spliced connection and modified spliced sleeve connection could be considered as a fixed end, whereas the use of screw-bolt-and-spring connections could be considered as a hinged end. The displacement ductility ratios of PLC insulation panels with an fc′ of 24.5 MPa were approximately 1.2 times higher than those of the counterpart PLC insulation panels with an fc′ of 13 MPa, because more severe cracks along the insulation materials were observed in the specimens with lower fc′ values.

Lateral Load Behavior of C-PSW/CFs Using Steel Members as Boundary Elements

Composite plate shear walls/concrete-filled (C-PSW/CFs), also known as SpeedCore systems, are a relatively new structural member in American codes and standards. Prior research has focused primarily on C-PSW/CF walls with either flange/closure plates or filled composite members as boundary elements. Walls without boundary elements have also been studied, but they are no longer permitted by the American Institute of Steel Construction (AISC 341-22). The reason is that composite walls without boundary elements do not provide adequate ductility for seismic design. This paper presents the results of experimental and numerical studies conducted to evaluate the cyclic lateral load behavior of C-PSW/CFs using hot-rolled structural steel members as boundary elements. The steel web plates of the C-PSW/CF specimens were connected to each other using threaded tie bars with double nut connections. Composite interaction between the steel and concrete infill was achieved using the tie bars and additional shear studs welded to the boundary elements. The composite walls were embedded and anchored to reinforced concrete foundation blocks using welded deformed bar anchors. The experimental investigations focused on the cyclic lateral load-drift responses including test observations and limit states, moment-rotation response of the plastic hinge and the section moment-curvature relationship, overall lateral stiffness, strength, and displacement ductility. The experimental results show that the specimens exceeded their nominal flexural capacities calculated using the plastic stress distribution method or fiber-based section modeling using measured material properties. The specimens had plastic hinge rotation capacity greater than 0.028 rad. and displacement ductility ratio greater than 5.2. Detailed 3D nonlinear inelastic finite element models and simpler fiber-based macro models of the tested specimens were developed and benchmarked using experimental results. The detailed 3D finite element models can reasonably simulate the global and local behavior of the specimens, and are recommended for conducting further parametric studies of composite wall design details. Simpler fiber-based macro models can efficiently simulate the cyclic lateral load behavior of the specimens, and are recommended for modeling C-PSW/CFs while simulating the behavior of multi-story building structures.

Tension resistance properties of hold-down and angle-bracket connections on cross-laminated timber (CLT)

The goal of this study was to propose a practical approach for predicting the tension resistance properties of hold-down (HD) and angle-bracket (AB) connections on cross-laminated timber (CLT) by using modified design equations. The effects of wood density and number of screws on the tension properties of screwed HD and AB connections were experimentally investigated. Pine CLT connections with lower wood density exhibited lower tension resistance (−39%) and yield displacement (−34%) but higher ductility ratio (91%) relative to those of larch CLT connections. The AB connections on larch CLT exhibited lower elastic stiffness (−25 to −53%) and tension resistance (−10 to −22%) than those of the HD connections. The different load distributions of the HD and AB connections led to different failure behaviors associated with wood species. Although the tension resistance of the CLT connections was directly proportional to the actual number of screws, the elastic tension stiffness of the CLT connections was not directly proportional to the actual number of screws. Based on these experimental results, group effects on the tensile properties of the HD and AB connections on CLT were accounted for in the design equations, and the difference between the elastic stiffness, tension resistance, and ductility ratio values predicted using the developed design equations and the corresponding experimentally obtained values were 8, 6, and 7%, respectively.

Comparison of Damage Indexes for Assessing Seismic Fragility of Bearings in an Offshore Bridge

This study analyzes the applicability of different damage indexes for bearings, focusing on the time-dependent deterioration of materials and the time-dependent bond-slip behavior between steel and concrete caused by chloride erosion. First, the methodology is proposed, encompassing the time-dependent deterioration of materials, the time-dependent bond-slip behavior, the quantification of different damage indexes of the bearing, and the fragility analysis for the bearings. Next, an offshore bridge is used as an example to investigate the detailed elements of the components and the time-varying effects. Thereafter, based on incremental dynamic analysis and fragility analysis, the discussion focuses on the comparison of damage indexes for assessing the seismic fragility of bearings in an offshore bridge. This study indicates that if the relative displacement ductility ratio is adopted as the criterion, the coverage of PGA obtained by the theoretical method is 167% greater than that obtained using the empirical method, and the relative displacement ductility ratio, which incorporates the shear deformation of piers, is better aligned with the performance-based ductility design concept and offers better economy. Safety-based damage indexes are recommended for the bridge in seismic zones, while economy-based indexes can be used in favorable bridge environments.

Cyclic flexural performance of precast lightweight aggregate concrete insulation panels

AbstractThis study investigated the structural safety of the developed panel‐to‐base joint technique for full‐size precast lightweight aggregate concrete (PLC) insulation panels subjected to cyclic lateral loads. The main parameters were the compressive strength of insulating concrete and the safety factor of the joint reinforcing bar for connecting with the base or beam. The test results revealed that the PLC insulation panel specimens with a safety factor of 1.0 experienced severe pinching effect and low ductile performance. However, the PLC insulation panel specimens with a safety factor of 1.6 exhibited higher flexural moment capacity, displacement ductility ratio, and work damage index than those with a safety factor of 1.0. Consequently, the overall flexural behavior of the PLC insulation panel specimens with a safety factor of 1.6 can be developed stably, resulting in satisfactory seismic connection performance requirements specified in NEHRP. Meanwhile, the developed panel‐to‐base joint using the joint reinforcing bar and L‐shaped steel plates can be considered as a fixed end according to the analysis of the collapse mechanism, as with spliced sleeve or welding plate joints.

Experimental Investigation on Seismic Performance of Non-Uniformly Corroded RC Moment-Resisting Frames

To investigate the effect of non-uniform corrosion on the seismic performance of reinforced concrete (RC) frame structures, seven RC frame specimens, including one uncorroded and six corroded frames, were tested under quasi-static loading. The damage modes, force-displacement hysteresis curves and skeleton curves, stiffness degradation, ductility and the energy dissipation capacity of specimens were studied. The influences of the corrosion degree, non-uniform corrosion characteristic value, and axial compression ratio on the seismic performance of the specimens were analyzed. The test results show that non-uniform corrosion of longitudinal bars has a significant effect on the development of seismic damage in RC frames. In comparison with non-corroded RC frames, the loading carrying capacity of corroded frames with non-uniform corrosion characteristics values of 0.18, 0.59, and 0.72 decreased by 8.5%, 14.8%, and 22.3%, the displacement ductility ratios decreased by 6.7%, 8.7%, and 10.0%, and the total cumulative energy dissipation at ultimate displacement values decreased by 24%, 41%, and 54%. For corroded frames with low axial compressive ratios, the loading carrying capacity and energy dissipation capacity rose with the increase in the axial compression ratio.

Experimental behavior of masonry infilled RC frames with openings strengthened by using CFRP strip

This study examines the general load-displacement behavior of reinforced concrete frames with opening masonry infill walls in different sizes and locations under lateral earthquake loading. In addition, a strengthening detail was developed with anchored CFRP strips to reduce the negative effects of openings in masonry infill walls on the performance of reinforced concrete frames with infill walls. Experimentally, it was investigated to what extent the proposed strengthening method could improve reinforced concrete frames and masonry infill walls with openings. The variables examined in this study were determined as the size of the openings left in the masonry infill walls and their location in the frame. As a result of the tests of the first series of test specimens in the experimental program, the negative effects of the openings left in the masonry infill walls on the performance of the infilled wall frame systems under the effect of earthquake loading were determined. Within the scope of the study, the effectiveness of the strengthening method with the infilled test specimens was determined in the second series. Within the horizon of the study, the strengthening method developed with anchored Carbon-Fiber-Reinforced-Polymers (CFRP) strips increased the ultimate load capacity, initial stiffness, displacement ductility ratio, and energy dissipation capacity values of the masonry infilled frame systems with opening by an average of 72%, 11%, 13%, and 10%, respectively.

Effect of synthetic zeolite on tobermorite synthesis

Chemical anchors are widely used in additional installations of construction irons, repair and reinforcement work. Due to the increasing diversity of materials and the improved awareness of waste products, it has become possible to produce different kinds of concrete, with various properties. In this study, class B420C ribbed bars with 16 mm diameter, were installed in four different concretes by using four different chemical adhesives, and a tensile force was applied. The stiffness, displacement ductility ratio, energy-dissipation capability and tensile force values were determined and the failure modes were interpreted from the load-displacement curves, obtained as a result of the experiments. It was found that the tensile force and energy-dissipation capacity, had increased as a result of installing anchor and applying a tensile force to the concrete, that was obtained by adding admixture materials, to the reference concrete. In the analytical part of the study, the formulation provided in ACI 318 was used, capacity and design strengths were identified, and their safety levels were determined in comparison with the test results.

A Numerical Study on the Seismic Performance of a Horizontal Dry Connection for Precast Concrete Shear Walls

Dry connections primarily consist of high-strength bolts and steel plates. They are commonly used in precast structures as they maximise time efficiency in the assembly stage compared with conventional methods. In this study, an embedded horizontal dry connection was developed using a square-shaped ring connector, high-strength hex nuts and flat washers, and grout for assembling precast concrete shear walls. Using Abaqus CAE 6.14, a numerical study was conducted on two full-scale RC shear walls including one monolithic and one precast specimen to assess the seismic performance of the bolted connection under the combined effect of axial and fully reversed cyclic loading. The average displacement ductility ratio of the precast specimen integrating the bolted connection was three times as much as the reference specimen. However, its relative energy dissipation capacity and shear strength were 21.94% and 27.92% lower, respectively. A parametric study was also carried out on the thickness and grade of the ring connector, grade of the vertical steel bars, number of ring connectors, and diameter of the vertical steel bars at the connection joints. Results showed that the seismic performance of the bolted connection was highly dependent on the bar diameter and number of ring connectors.

LEGO-Inspired and Digitally-Fabricated steel reinforcement cage for Ultra-High performance concrete (UHPC) beams

Reinforced concrete is one of the most used structural configurations in the world, but the production of reinforcement cage is a labor-intensive, time-consuming and strenuous task. This study develops a new LEGO-inspired reinforcement cage system that is digitally fabricated through waterjet cutting, which can be assembled in three steps. The experimental program tests two ultra-high performance concrete (UHPC) beams reinforced by this LEGO-cage system, one with smooth surface and one with deformed ribs. Results show that including deformed ribs slightly increase the post-cracking stiffness of the beams while both beams exhibit a post-yielding plateau and a displacement ductility ratio over 8. An existing UHPC flexural model predicts the flexural strength (both yield and maximum strength) of the LEGO-cage-reinforced beams with errors below 4%. A two-dimensional finite element model, which is originally developed for rebar-reinforced UHPC, is found to well predict the load–displacement responses of LEGO-reinforced UHPC beams. A cost analysis reveals that adopting this new cage system can reduce the production cost and manual labor time by over 17% and 86%, respectively.

Experimental investigations the effects of dusty, humidity and temperature conditions on chemical anchors

Chemical anchor applications are frequently used to add new structural elements to existing structures. Chemical anchors can be applied quickly and easily, if anchors apply according to a detailed installation and cleaning procedure depending on environmental conditions and workmanship. In this work, the relationship between the axial tensile capacity of chemical anchors and the effect of dust, humidity, and temperature were examined as adverse conditions. The effect of using different conditions, anchorage diameters and embedment depth on the tensile strength of the anchors was evaluated. In the experimental study, anchors diameter 12, 16 and 20 mm were selected to be used as anchors. The depth of embedding was determined to be 5, 10, 15 and 20 times the diameter of used anchors. The initial stiffness, displacement ductility ratio, energy absorption capacity, failure modes, and safety levels according to ACI 318 were obtained by using the load-displacement curves. According to the parameters considered in the experimental program, the most unfavorable situation was obtained in anchors embedded in a wet environment. In addition, it was observed that the diameter of the drilled holes causes a decrease in the axial tensile capacity by increasing the exposure time of the anchors to water and temperature.