Increase In Ultimate Strength Research Articles

An improved cable-cylinder bracing system with quarter-ring yielding devices for seismic retrofit of steel moment frames

This study proposes an innovative hybrid lateral load-resisting system, termed the ring-cable-cylinder bracing system, aimed at improving the energy dissipation capacity and ductility of the previously introduced cable-cylinder bracing (which offers relatively the same level of seismic energy dissipation and ductility as the original bare steel frame), and minimizing the damage to the beam-to-column connections via utilizing quarter-ring curved yielding devices. First, the proposed bracing system and its working mechanism are introduced. A mathematical procedure based on the theorem of the least work and the method of virtual work is then presented to derive highly-accurate, practical, and easy-to-use equations for calculating the thickness of the utilized quarter-ring yielding devices. The design requirements for these curved devices, based on the characteristics of the frame in which they are utilized, are also discussed exhaustively. In the next step, the presented formulae’s accuracy and usability are comprehensively investigated by conducting a finite element parametric study. The results show that the proposed system can provide an extra source of energy dissipation and ductility. It was also observed that the new system leads to an increase in both initial stiffness and ultimate strength and limits the pinching phenomena in the hysteretic cycles.

Axial compressive behavior of concrete filled stainless-carbon steel tube columns: Experimental investigation

This paper investigates the axial compressive behavior of concrete-filled stainless-carbon steel tube (CFSCT) stub columns, consisting of an outer stainless steel tube, an inner carbon steel tube, and infilled concrete. A total of twenty column specimens are fabricated and tested. Test parameters include column section type, strength and wall thickness of carbon steel tube, and concrete strength. Failure modes, load versus deformation relationships, ultimate strength, residual strength, ductility, elastic and elastic-plastic local buckling stress, and strain characteristics are investigated. Results show that outward local buckling of stainless steel tubes occurs in all CFSCT column specimens, and columns fail in a ductile manner. Increasing the carbon steel tube thickness can significantly improve column ultimate strength and residual strength. Compared to conventional concrete-filled stainless steel tube (CFSST) columns, the ultimate strength of CFSCT columns improved by 10.9%, 23.1%, and 27.4% on average for columns with carbon steel tube wall thickness of 2, 4, and 6 mm, respectively. The post-peak ductility behavior is also related to carbon steel tube wall thickness, increasing wall thickness can slow down the descending branch after peak load. Concrete has significant effect on the ultimate strength, when concrete strength increases, specimen ultimate strength increases by 15.1% on average. In addition, finite element model is established and analyzed based on the experimental results. Finally, ultimate strengths are compared and evaluated according to the Eurocode 4, AIJ, ACI and GB 50936.

Determination of mechanical properties of two-phase and hybrid nanocomposites: experimental determination and multiscale modeling

Abstract In this paper, the effects of filler content and the use of hybrid nanofillers on agglomeration and nanocomposite mechanical properties such as elastic moduli, ultimate strength and elongation to failure are investigated experimentally. In addition, thermoset epoxy-based two-phase and hybrid nanocomposites are simulated using multiscale modeling techniques. First, molecular dynamics simulation is carried out at nanoscale considering the interphase. Next, finite element method and micromechanical modeling are used for micro and macro scale modeling of nanocomposites. Nanocomposite samples containing carbon nanotubes, graphene nanoplatelets, and hybrid nanofillers with different filler contents are prepared and are tested. Also, field emission scanning electron microscopy is used to take micrographs from samples’ fracture surfaces. The results indicate that in two-phase nanocomposites, elastic modulus and ultimate strength increase while nanocomposite elongation to failure decreases with reinforcement weight fraction. In addition, nanofiller agglomeration occurred at high nanofiller contents especially higher than 0.75 wt% in the two-phase nanocomposites. Nanofiller agglomeration was observed to be much lower in the hybrid nanocomposite samples. Therefore, using hybrid nanofillers delays/prevents agglomeration and improves mechanical properties of nanocomposite at the same total filler content.

Local Composition Migration Induced Microstructural Evolution and Mechanical Properties of Non-equiatomic Fe40Cr25Ni15 Al15Co5 Medium-Entropy Alloy

A newly designed composition of non-equiatomic Fe40Cr25Ni15Al15Co5 medium-entropy alloy (MEA) was produced by induction melting (IM). The as-cast alloy was found to consist of a two-phase microstructure of BCC (2.87 ± 0.01 A) and ordered B2 (2.88 ± 0.02 A) type phases. The structures of these phases were confirmed through X-ray diffraction (XRD) and transmission electron microscopy (TEM) techniques. It was observed that the Ni-Al-enriched ordered B2 phase of cuboidal shapes (~ 100 to 200 nm) is homogeneously distributed in Fe-Cr-rich BCC matrix with a cube-on-cube orientation relationship. The formation of the columnar dendrites (width 50 to 100 μm) was identified through optical microscopy (OM). The structural and microstructural stability of the alloy was investigated by heat-treating the alloy through different schedules. Heat-treated samples at different temperatures (< 1273 K) exhibit a similar type of two-phase microstructure with columnar dendrites. However, compositional rearrangement takes place during long time exposure to develop polymorphically related phases. The alloy was observed to possess a high compressive yield strength and hardness, i.e., ~ 1047 MPa and 391 ± 9 HV, respectively, at room temperature. Heat-treated samples at 600 °C and 900 °C (873 K and 1173 K) showed an increase in yield strength and ultimate strength with a significant increase in plasticity due to the increase in volume fraction of B2 phase and softening of the BCC matrix phase. The thermal stability and high strength of this alloy may open new avenues for high-temperature applications.

Study of Influence of Climatic Factors of North on Properties of Polymer Composite Textolites

Influence of a very cold climate on properties of basalt and glass textolites made by an infusion method by successively laying a reinforcing material on a mold and impregnating with a three-component epoxy binder is studied. Full-scale climatic tests at an open proving ground during 2 years led to a decrease of ultimate tensile strength by 14% and an increase of ultimate bending strength by 18% for the basalt textolite, the increase of the ultimate tensile strength by 9% and the ultimate bending strength by 22% for the glass textolite. Conducted studies of changes of surface relief showed insignificant variations of average amplitude of inhomogeneities up to 0.4 μm for the basalt textolite and up to 4 μm for the glass textolite. The conducted studies of these materials demonstrated their resistance to the climatic influences in a region of the very cold climates, which is confirmed by a high level of preservation of their strength parameters.

Study of Bond Strength of Plain Surface Wave Type Configuration Rebars with Concrete: A Comparative Study

This study investigates the bond strength behaviour of plain surface wave type configuration (PSWC) rebars in comparison to mild steel (MS) and high yield strength deformed (HYSD) rebars of varied rib configuration as per BIS and ASTM standards. The variables in the rebar include plain surface, curved surface, parallel rib, diamond rib and Nano modified cement polymer anticorrosive coating (CPAC). Total of 30 pull-out specimens and 12 beam-end specimens were put to a pull-out test following BIS and ASTM standard respectively. The load corresponding to 0.025mm free end (FE) slip and 0.25mm loaded end (LE) slip were carefully observed. The load-deflection behaviour, appearance of the first crack in the specimens and ultimate failure load was recorded. The experimental results showed that as compared to MS rebars, HYSD rebars offer an approximately threefold increase in ultimate bond strength and 1.5 times increase in usable bond strength irrespective of varied rib configuration. PSWC rebars with 4mm offset and 80mm pitch offered 2.4 times increase in ultimate strength and 76.2% increase in usable bond strength as compared to MS rebars. The ultimate pull-out load of PSWC rebars was around 25% and the usable bond strength was only 8.6% lesser than HYSD rebars with parallel ribs. The adopted coating enhanced the corrosion resistance and the reduction in bond strength with any surface configuration was less than the permissible maximum reduction of 20% as specified in IS 13620-1993. Hence it can be concluded that PSWC rebars offered promising bond strength results and upon further optimization and study in other aspects, PSWC rebars can be a way to replace HYSD rebars in future for enhancing concrete durability at zero added cost.

Effect of thermomechanical treatment on the microstructure and mechanical properties of a low-carbon low-alloy steel

The effect of thermomechanical treatment on the microstructure, tensile strength and impact toughness of low-carbon low-alloy steel is considered. The developed microstructure is characterized by grain elongation along the rolling direction. Both the yield strength and the ultimate tensile strength increase with a decrease in test temperature. The ultimate strength at room temperature is 797 MPa, and at 77 K the ultimate strength increases to 1198 MPa. The steel samples subjected to tempforming exhibit impact toughness of KCV = 410 J/cm2 at room temperature. A decrease in the test temperature to 233 K leads to a slight decrease in the KCV value to 340 J/cm2. It should be noted that the impact specimens are not completely fractured even at a test temperature of 233 K, suggesting higher real values of impact toughness.

The Use of Suture Augmentation for Graft Protection in ACL Reconstruction: A Biomechanical Study in Porcine Knees

PurposeTo biomechanically evaluate the use of the suture augmentation construct at time 0 of ACL reconstruction.MethodsEighty porcine knees underwent ACL reconstruction using 2 techniques for graft fixation: a single suspensory construct (SSC), performed with a femoral button and tibial interference screw; and a double suspensory construct (DSC), with a femoral and tibial button. Each fixation technique was performed on 40 porcine knees divided into 4 subgroups. The first group had a nonaugmented ACL reconstruction, the second group had an ACL reconstruction with suture augmentation, and the third and fourth groups were the same as the first and second groups, with the graft resected 80% to simulate graft weakening. Ultimate load, yield load, stiffness, cyclic displacement values, and mode of failure were recorded for each graft.ResultsIn a weakened graft model with 80% graft resection, there was a significant increase in ultimate strength (P < .001), yield strength (P < .001), and cyclic displacement (P < .001) with suture augmentation. There was no significant increase in stiffness with suture augmentation with either construct (P = .278). In the setting of an intact graft, there were no differences in either SSC or DCS groups with or without suture augmentation.ConclusionsThe addition of a suture to ACL reconstruction techniques resulted in minimal changes in baseline biomechanical characteristics while improving ultimate load, yield load, and cyclic displacement in a weakened graft model.Clinical RelevanceSuture augmentation of ACL reconstruction may confer improved integrity of the graft and is worth consideration and future clinical study.

Reinforcement effect of pulp fines and microfibrillated cellulose in highly densified binderless paperboards

This study investigates the use of papermaking fines as a reinforcement fibre for fully bio-based highly densified paperboards. Paperboards were prepared in a wet process followed by subsequent densification, aiming to exploit the self-bonding capabilities of cellulosic fibres without addition of synthetic binders. The cohesion of paper-based materials can be mainly attributed to the presence of strong hydrogen bonds which effectively interlink individual pulp fibres especially in highly densified paperboard. However, at a given board density, cohesion of pulp fibres may be further enhanced by adding micro- or nanoscale cellulosic fibres which provide a high surface area and thus enable extensive hydrogen bonding. In the present study, primary papermaking pulp and microfibrillated cellulose (MFC) were used to mechanically reinforce highly densified paperboards prepared from unrefined kraft pulp. All fibre materials used were characterised with regard to morphology, size distribution and dewatering behaviour (Schopper-Riegler freeness). The prepared paperboards were characterised in uniaxial tensile tests and fracture surfaces were investigated by scanning electron microscopy. As revealed by tensile tests, both reinforcement materials were highly effective, resulting in an ultimate strength increase of 50% for primary fines and 60% for MFC. Even at an addition level of 1 wt%, both reinforcement materials increased board strength by around 25%. In terms of mechanical properties, the paperboards produced in this study were found to be competitive to densified paper-based materials described in literature and similar boards which are already commercially available.

Hollow silica reinforced magnesium nanocomposites with enhanced mechanical and biological properties with computational modeling analysis for mandibular reconstruction

The present study investigates Mg-SiO2 nanocomposites as biodegradable implants for orthopedic and maxillofacial applications. The effect of presence and progressive addition of hollow silica nanoparticles (0.5, 1, and 1.5) vol.% on the microstructural, mechanical, degradation, and biocompatibility response of pure Mg were investigated. Results suggest that the increased addition of hollow silica nanoparticles resulted in a progressive increase in yield strength and ultimate compressive strength with Mg-1.5 vol.% SiO2 exhibiting superior enhancement. The response of Mg-SiO2 nanocomposites under the influence of Hanks’ balanced salt solution revealed that the synthesized composites revealed lower corrosion rates, indicating rapid dynamic passivation when compared with pure Mg. Furthermore, cell adhesion and proliferation of osteoblast cells were noticeably higher than pure Mg with the addition of 1 vol.% SiO2 nanoparticle. The biocompatibility and the in vitro biodegradation of the Mg-SiO2 nanocomposites were influenced by the SiO2 content in pure Mg with Mg-0.5 vol.% SiO2 nanocomposite exhibiting the best corrosion resistance and biocompatibility when compared with other nanocomposites. Enhancement in mechanical, corrosion, and biocompatibility characteristics of Mg-SiO2 nanocomposites developed in this study are also compared with properties of other metallic biomaterials used in alloplastic mandibular reconstruction in a computational model.

Effects of Different Core Suture Lengths on Tensile Strength of Multiple-Strand Sutures for Flexor Tendon Repair

PurposeTo compare 2 types of newly devised 8-strand quadruple-looped suture (QLS) techniques with a 6-strand triple-looped suture (TLS) technique; and to assess the effects of different core suture lengths (CSLs) (the length between 2 locking sites of a suture strand) within each suture row on tensile strength.MethodsWe repaired 24 flexor tendons from 12 rabbits using the TLS and QLS techniques, with equal CSL (QLS) or unequal CSL (unequal QLS) among each suture row. The QLS was composed of 4 looped sutures on the anterolateral and posterolateral aspects of the tendon. The cross-sectional area of the locking portion of each thread in the QLS was equal to that in the TLS. In the QLS technique, the CSL on each aspect of the tendon was 13 mm. In the unequal QLS technique, the CSL on each aspect of the tendon was 13 and 17 mm. The load at 1- and 2-mm gaps, the maximum load until the 3-mm gap, and the ultimate load were compared among the 3 techniques.ResultsThe QLS was significantly stronger than the unequal QLS and the TLS for loads at 1-mm and 2-mm gaps, maximum load until 3-mm gap, and ultimate load. There was no significant difference between the unequal QLS and TLS techniques. The QLS technique showed an approximately 30% increase in gap resistance and ultimate strength compared with the TLS technique.ConclusionsThe QLS technique showed an estimated increase in tensile strength proportional to the number of suture strands compared with the TLS technique. Our study suggests that a consistent CSL in each suture row provides the highest strength in multistrand sutures consisting of the same configuration of suture rows.Clinical relevanceThe QLS technique may reduce the risk for tendon rupture associated with early active mobilization after flexor tendon repair.

Mechanical properties of Q345 structural steel after artificial cooling from elevated temperatures

Water cannot be used to effectively extinguish fires that occur in chemical plants, oil and gas pipelines, and other flammable and combustible liquid storage structures. In such cases, firefighting foam is often used as a fire-extinguishing agent. In this study, we experimentally investigate the mechanical properties of Q345 steel after subjecting it to temperatures of 200–900 °C, followed by artificial cooling using water or firefighting foam. The fire-affected specimens are subjected to tensile tests to observe their fracture characteristics and obtain their stress–strain curves. Below an exposure temperature of 600 °C, the mechanical properties of Q345 steel remain almost entirely unchanged, irrespective of the cooling method. Above 600 °C, the mechanical properties of Q345 steel experience significant changes based on the exposure temperature and the type of cooling method. When Q345 steel is exposed to temperatures of 800 °C and 900 °C and cooled using water, its yield strength and ultimate strength increase significantly. In contrast, the ductility of the Q345 steel that is water cooled from temperatures of 600–900 °C rapidly decreases with the increase in temperature. When Q345 steel is exposed to temperatures of 600–900 °C and cooled using firefighting foam, it experiences a significant reduction in both yield strength and ultimate strength. In contrast, the ductility of Q345 steel that is cooled using firefighting foam does not change significantly. Subsequently, the macroscopic and microscopic fracture morphologies are also analyzed to better understand the changes in the mechanical properties of Q345 steel. Finally, empirical equations are proposed to predict the mechanical properties of fire-affected Q345 steel that is cooled using water or firefighting foam.

Influence of Consolidation Pressure on Stress-Deformation Responses of Bio-mediated Residual Soil in Malaysia

ABSTRACT Microbial-induced calcite precipitation has recently emerged as an attractive sustainable ground improvement technique. In present study, the stress-deformation responses of a bio-mediated residual soil in Malaysia were investigated through undrained triaxial compression tests with different isotropic consolidation pressures. A practical and effective bio-mediation treatment method for residual soil was proposed. Bio-mediation increased the residual soil isotropic yield stress from 40 kPa to 100 kPa attributed to the greater inter-particle resistances contributed by calcite precipitation. The soil compression index was also reduced from 0.188 to 0.071. The bio-mediated residual soil showed a greater radial resistance than its untreated counterpart when subjected to an isotropic pressure. Under isotropic consolidation pressure below the yield stress, the shear strength of bio-mediated soil was governed predominantly by the calcite content. However, beyond the yield stress, the calcite bonds would diminish and only a slight increase of ultimate shear strength was observed attributed to calcite densification.

Nested size effects in the nanoindentation response of additively manufactured 316L stainless steel

Recent work has shown that the presence of cellular substructures in selectively laser melted (SLM) 316L stainless steel coincides with significant increases in yield stress and ultimate strength. These substructures have been associated with dislocation cell formation, with cell walls and cell interiors corresponding to regions of high and low dislocation density, respectively. Motivated by this finding, the present effort seeks a more comprehensive understanding of this phenomenon through spatially resolved hardness mapping via nanoindentation. Initially it was assumed that a spatially varying “cellular” hardness pattern would emerge, corresponding to the geometry and the characteristic features (cell walls and cell interior) of the cell structure. However, due to multiple, simultaneously operating hierarchical size effects, the apparent hardness deviates from this anticipated behavior. Direct evidence is provided in the present work indicating that these size effects are due to the indenter, characteristic sub-structural length, and grain size. Analysis of the load/displacement behavior enabled observation of each of these size effects, independent of the local anisotropy due to crystal orientation.

Strengthening rectangular columns using recycled PET bottle strips

Consumption of plastic is steadily increasing, making disposal through landfilling, incineration, and open-or closed-loop recycling challenging. The majority of these plastic waste is Polyethylene Terephthalate (PET) bottles, widely used for single-use beverage and liquid containers. This study focuses on using Recycled PET (RPET) bottles as confining material on rectangular concrete columns. This method uses RPET strips that are produced by stripping parts of the RPET bottle which are then wrapped around externally on concrete columns. It can easily be adapted in rural areas with low skilled workers, unlike the conventional methods which makes use of expensive materials and require trained workers. Production of twenty-seven rectangular unreinforced concrete specimens with a size of 100 mm × 100 mm × 300 mm are made. The RPET strips are varied having width of 10 mm and 20 mm, and clear spacing between strips of 10 mm and 25 mm by using two available PET bottles in the industry. A fastening system is proposed, instead of using industrial adhesives, in placing and tying the RPET strips to the rectangular column. Results show a 19% to 70% increase in ultimate compressive strength for rectangular columns which are externally reinforced by RPET. A significant increase in axial strain from the stress-strain diagram is experienced. The proposed method is practical and effective in strengthening concrete structures. The findings suggest that test for long-term durability should be implemented. Life cycle analysis as well as further studies on the scalability of this viable PET waste management solution should be conducted.

Anisotropic behavior in bending of 3D printed concrete reinforced with fibers

The incorporation of fibers is an effective way for the reinforcement of 3D printing concrete. However, researches referring to effect of fibers on the anisotropy properties were limited. Therefore, the anisotropic behavior of fiber reinforced cement-based material for 3D printing under bending were carefully examined. With the addition of polyethylene (PE) fibers, the specimen failure was no longer dominated by the weak interface and the flexural strengths in all of the three directions were significantly improved. The post-peak performance was directly related to the content of fibers and a suitable fiber length should be selected. Microstructure analysis showed that the uniform and aligned orientation fibers were key factors leading to the increase of ultimate strength and post-peak behavior. However, 3D printed specimens still demonstrated obvious anisotropic behavior. The flexural strengths in the directions parallel and perpendicular to the printing element within the printing plane were highest and performed similarly, while the strength in the direction orthogonal to the printing plane (across the layers) was the lowest. It is believed the findings can provide help for understanding the role of PE fibers in extrusion-based 3D printing concrete.

Flash Welding of Microcomposite Wires for Pulsed Power Applications

This paper presents the experimental results of Cu-Nb wire joining upon applying flash welding technology. The present research is aimed at investigating the structure, electrical and mechanical properties of butt welding joints of Cu-Nb conductors, usable for coils of pulsed magnetic systems. The butt joint structure was found to be free of welding defects. The structure of the butt welded joint provides an insignificant increase in electrical resistance and sufficient ultimate strength and plasticity of the joint. The tensile strength of the welded sample reaches 630 MPa.

Behavior of Strengthened RC Beams with CFRP Sheets under Combined Bending and Torsion

The experimental investigations were carried out to study the behavior of reinforced concrete beams strengthened by CFRP sheets under different loading conditions (pure bending, combined bending and torsion and pure torsion). The experimental work included testing twenty RC beams of the rectangular cross-section of dimensions of 160×240 mm and of 2600 mm length with an area of the ordinary reinforcement being kept constant for all beams. Two parameters were taken into consideration (Twisting to bending moment ratio (T/M) and CFRP strengthening pattern). The tested beams are divided into five groups. Each group consists of four beams; the first beam is without CFRP strengthening, the other three are strengthened with CFRP sheets of different arrangements (U-stirrups, U-stirrups and longitudinal CFRP sheets in the bottom and Full U- stirrups wrapping). Each beam is loaded to a different loading conditions (pure bending, T/M = 0.5, T/M = 1.0, T/M = 2.0 and pure torsion). The CFRP sheets were attached externally to the beam. Test results were analyzed based on the influence of CFRP on the ultimate load, vertical mid-span deflection and failure modes. In the experimental work, it was found that all strengthening patterns of CFRP sheets exhibited a significant increase in ultimate strength. This increase reached up to 78.9% for tested beams, when the beam strengthened in the form of full U- stirrups wrapping pattern for T/M = 0.5. In this study, it is observed that the use of external CFRP sheets attached to the tension sides of beams (U-stirrups and longitudinal CFRP in the bottom) could enhance the ultimate load capacity by 32.7% over the capacity of the unstrengthen control beam for T/M = 1.0.

Numerical Investigations on Behavior of Strengthened RC Beams with CFRP under Combined Bending and Torsion

The numerical investigations were carried out to study the behavior of reinforced concrete beams strengthened by CFRP under different loading conditions (pure bending and combined bending and torsion). The numerical work included analysis of eight experimentally tested beams of rectangular cross-section dimensions of (160×240) mm and (2600) mm length keeping the area of the ordinary reinforcement constant for all beams. The following parameters were taken into consideration, twisting to bending moment ratio (T/M) and CFRP strengthening arrangement. The analyzed beams are divided into four groups. Each group consists of two beams; the first beam is without CFRP strengthening, the other beam is strengthened with CFRP. Each beam is loaded to a different loading conditions (pure bending, T/M=0.5, T/M=1.0, T/M=2.0). The CFRP sheets were attached externally to the beam. Analysis results were analyzed based on influence of CFRP on ultimate load and vertical mid-span deflection. According to the numerical study, it was found that all strengthening arrangements of CFRP sheets exhibited a significant increase in ultimate strength. The three-dimensional (3D) finite element model (FEM) utilized in present work is capable to simulate the behavior of externally strengthened reinforced concrete beams by CFRP. Full bond connections (no slip) are assumed between the CFRP sheets and surface of concrete. The comparison between the numerical and the experimental results declared the validity of the numerical analysis where the range of the (Pexp./PANSYS) ratio in ultimate load was from 0.847 to 1.157. The general behavior of the (FEM) shows good agreement with the test results from the experimentally tested beams.

Effect of longitudinal steel reinforcement ratio on deflection and ductility in reinforced concrete beams

This search report is an experimental result on load –deflection relationship of various ratios of longitudinal reinforcement for six simply supported reinforced concrete beams. All specimens’ dimensions are (200×300×1750mm) and they were tested under two-point loading. Concrete compressive strength was (37.0-40.7 MPa). The variables studied in this work were tensile steel ratio (0.46-3.0%), bar diameter (12, 16 and 25mm) and number of bars (2 or 3 bars). It is concluded that for low reinforcement values (ρ < 0.013), an increase in ρ is sharply reduced the ductility index μ d . However, this effect decreases with increase in ρ values. All beams exhibit insufficient displacement ductility (less than 3) when reinforced with ρ/ρ b > 0.4. The increase in longitudinal steel ratio using 2 bars is more significant than when using 3 bars in yield and ultimate strengths of specimens as well as the deflection values at yield load, but the deflection values have gradual decrease at the ultimate load as a result of ductility decrease. It was concluded that the increase in longitudinal reinforcement ratio causes an increase in yield and ultimate strength of beams, these increments are compatible with the steel ratio i.e. by increasing the ρ by 50% the strength is increased about this ratio. As well as, the decreasing in ductility compatible with increasing the ρ by 50% the ductility decreased in about 50% on average.