Strand Diameter Research Articles

Bond-Slip Behavior of High-Strength Stainless Steel Wire Mesh in Engineered Cementitious Composites: Numerical and Theoretical Analysis.

This study introduces high-strength non-prestressed steel strands as reinforcement materials into Engineered Cementitious Composites (ECCs) and developed a novel high-strength stainless-steel-strand-mesh (HSSWM)-reinforced ECC with enhanced toughness and corrosion resistance. The bonding performance between HSSWM and an ECC is essential for facilitating effective cooperative behavior. The bond behavior between the HSSWM and ECC was investigated through theoretical analysis. A local bond-slip model was proposed based on the average bond-slip model for HSSWM and ECCs. The results indicated that the local bond-slip model provided a more accurate analysis of the bonding performance between HSSWM and the ECC compared to the average bond-slip model. The effects of the ECC's tensile strength, steel strand diameter, and transverse strand spacing on local bond-slip mechanical behavior were investigated through FEA. The results showed that the local bond-slip model and FE results aligned well with the experimental data. Additionally, the distribution of bond stress between the HSSWM and the ECC was analyzed using the micro-element method based on the local bond-slip model. A prediction model for the critical anchorage length and bond capacity of HSSWM in the ECC was established, and the accuracy of the model was verified.

Numerical modeling of the transfer length of 17.8 mm (0.7 in) diameter prestressing strands in pretensioned members

The bond between concrete and reinforcing steel bars in reinforced concrete structures is crucial. Prestressing strands with a diameter of 17.8 mm (0.7 in) transfer higher compression per unit area than smaller strands, improving moment capacity and shear strength and extending the girder span. However, limited research on the bond performance of these 17.8 mm diameter prestressing strands has restricted their widespread use despite their advantages. This study presents a methodology to determine the transfer length of pretensioned members numerically. The influence of pretension force and bond strength on a 17.8 mm diameter strand was assessed through the validation of a finite element model using experimental results from a standardized pretensioned pull-out test. Analytical calculations using different code formulas were also conducted, encompassing strands of varying diameters. Our finite element analysis suggests that a 50.8 mm spacing between adjacent 17.8 mm diameter strands is applicable, ensuring there is no stress overlap in the transfer zones, which can lead to concrete cracking and reduced structural integrity. Existing code formulas, such as ACI 318–19 and AASHTO LRFD 9th edition, require longer transfer lengths when compared with the numerical results. The fib MC 2010 and EC2 formulas offer closer results to numerical results of smaller diameter strands but underestimate the transfer length for the 17.8 mm diameter strand. Therefore, improvements to code formulations may be necessary for more accurate transfer length predictions for this specific strand size.

Cyclic bond behavior and bond stress – slip model of steel strands in steel fiber reinforced concrete

To study the bond performance of steel strands in steel fiber reinforced concrete (SFRC), bonding tests under monotonic and cyclic loads were performed on the specimens with different steel fiber volume fractions (SFVFs), bond lengths, nominal diameters of steel strands and SFRC strengths. The results showed that the relative rotation between the steel strand and SFRC occurred when the steel strands were vertically pulled out from SFRC due to the smooth and continuous helical shape of the steel strands. For the specimens with the same parameters, the maximum bond stress under cyclic load decreased by 1.67–22.88 % than that under monotonic load. The maximum bond stress under cyclic load increased with the increasing SFVFs or SFRC strength. Notably, the maximum bond stress under cyclic load also increased with the increasing bond length or diameter of steel strands, significantly different from that of ordinary ribbed steel bars and FRP bars. The cumulative energy dissipation (CED) of bond specimens increased with the diameter of steel strands and SFRC strength. Besides, the SFVFs had a positive effect on the CED, but simultaneously increasing diameter of steel strands would weaken the positive effect of SFVFs, and simultaneously increasing bond length had no obvious on the CED. Finally, a bond stress – slip model of steel strands in SFRC was established, suitable for calculating bond stress – slip curves under random and complicated loading schemes. By comparing the calculation and test results of bond stress – slip curves, it was proved that the proposed model had an acceptable accuracy and could describe the influence laws of SFVF, bond length, nominal diameter of steel strand and SFRC strength well.

Optimizing Production, Characterization, and In Vitro Behavior of Silymarin-Eudragit Electrosprayed Fiber for Anti-Inflammatory Effects: A Chemical Study.

Inflammatory Bowel Disease (IBD) is a chronic condition that affects approximately 1.6 million Americans. While current polyphenols for treating IBD can be expensive and cause unwanted side effects, there is an opportunity regarding a new drug/polymer formulation using silymarin and an electrospray procedure. Silymarin is a naturally occurring polyphenolic flavonoid antioxidant that has shown promising results as a pharmacological agent due to its antioxidant and hepatoprotective characteristics. This study aims to produce a drug-polymer complex named the SILS100-Electrofiber complex, using an electrospray system. The vertical set-up of the electrospray system was optimized at a 1:10 of silymarin and Eudragit® S100 polymer to enhance surface area and microfiber encapsulation. The SILS100-Electrofiber complex was evaluated using drug release kinetics via UV Spectrophotometry, Fourier-Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and Differential Scanning Calorimetry (DSC). Drug loading, apparent solubility, and antioxidant activity were also evaluated. The study was successful in creating fiber-like encapsulation of the silymarin drug with strand diameters ranging from 5-7 μm, with results showing greater silymarin release in Simulated Intestinal Fluid (SIF) compared to Simulated Gastric Fluid (SGF). Moving forward, this study aims to provide future insight into the formulation of drug-polymer complexes for IBD treatment and targeted drug release using electrospray and microencapsulation.

Parametric Study on Transversely Cracked Precast Prestressed Concrete Bridge Deck Girders with Rectangular Voids

Transverse cracks in precast prestressed concrete (PPC) bridge deck girders cause a notable increase in strand stresses and adversely affect the cracked girder’s capacity and durability. This numerical study analyzes the impact of transverse cracks on the behavior of PPC bridge deck girders by relating the crack width to the residual capacity, stresses, and load rating of the cracked girders. A non-linear finite element (FE) model is developed to understand the behavior and predict the stresses in an in-service PPC bridge deck girder damaged by a transverse crack. The residual capacity and built-up stresses obtained from the FE model are used in the load rating analysis of the cracked PPC bridge deck girder. A parametric study is conducted to understand the effect of the influencing parameters, such as the girder geometry and material properties, on the damaged girder’s behavior. For an 838 mm × 914 mm PPC deck girder, the statistically significant parameters are found to be the span length ( L), strand diameter ( db), and skew angle ([Formula: see text]). From the numerical analysis of the in-service PPC bridge deck girder, the load rating is predicted to be governed by the capacity for the existing 0.25 mm crack. In the parametric study of the 838 mm × 914 mm PPC deck girder, the inventory rating factor of the prestressing strands in tension is predicted to decrease linearly for crack width up to 0.64 mm, while the capacity inventory rating factor is predicted to decrease by up to 73.8% for the crack width of 0.64 mm.

Finite Element Analysis of Load-Bearing Characteristics and Design Method for New Composite-Anchor Uplift Piles

This paper introduces a new type of uplift pile known as the composite-anchor pile, which employs a composite anchor composed of steel strands, grouting materials, and steel pipes as the main reinforcement. This paper extensively analyzes this pile’s load-bearing capacity and deformation characteristics through full-scale field tests and three-dimensional finite element numerical simulations. The results show that the composite-anchor pile has a more even distribution of stress, and its endurance and mechanics performance are better than others. Furthermore, this study utilizes a three-dimensional finite element refined model that has been validated using on-site test results to examine the influence of key parameters, such as the pile diameter, the number of composite-anchor cables, and the diameter of steel strands, on the load-bearing capacity of uplift piles. Building upon these findings, this paper introduces a calculating method to determine the bearing capacity of composite-anchor piles, thereby addressing the existing gap in this field.

Waste‐Valorized Nanowebs for Crystal Violet Removal from Water

Lightweight, metal‐free, sustainable, and reusable adsorbent materials are of paramount significance in addressing the challenges of wastewater treatment. Accordingly, semi‐crystalline nanocellulose (NC) is extracted from tissue paper waste and used to modify polyacrylonitrile (PAN) to produce electrospun nanowebs with strand diameters from ≈180–300 nm. The incorporation of NC into PAN is confirmed by infrared and Raman spectroscopy and X‐Ray diffraction. When tested for crystal violet (CV) adsorption, NC‐modified PAN (20% NC@PAN) exhibits the highest CV removal capacity, achieving 91–94% removal over three cycles each, demonstrating exceptional recyclability. In contrast, unmodified PAN significantly decreases in CV adsorption capacity (from 59% to 48% in the third cycle), possibly due to an increased (≈36%) nanofiber diameter. The adsorption kinetics, exhibiting pseudo‐second order, interparticle (in between nanofibers) diffusion, and Elovich kinetic models emphasize the role of multilayer CV adsorption through reversible chemical interactions. Confocal micro‐Raman spectroscopy unveils a multifaceted CV adsorption mechanism, suggesting both surface and multilayer diffusion, with NC‐enhancing interactions. These findings demonstrate the potential of NC‐modified PAN nanowebs as effective and environmentally sustainable adsorbents for removing CV from aqueous solutions, suggesting promising practical applications.

Novel conductor design to increase the thermal rating of overhead lines

In this paper the performance of existing and novel designs of overhead bare conductors with regard to their capacity to evacuate the heat generated by ohmic losses is compared. The effect of both the diameter of strands and the external shape of the conductor on the convective heat transfer capacity are evaluated with a finite element method commercial software for an ACSR conductor with different diameter strands, wind velocities and conductor current, resulting in a design that improves the customary design by around a 7 % of thermal rating.

Investigation on Seismic Behavior of Prestressed Steel Strand Composite Reinforced High-Strength Concrete Column

To study the seismic performance of high-strength concrete columns reinforced with prestressed steel strands, five column specimens were designed and tested with varying parameters, such as axial compression ratio (0.2, 0.35, 0.5) and diameter of steel strands (9.5 mm, 11.1 mm, 12.7 mm), under low-cyclic reversed loading. The failure modes, hysteretic curves, stiffness degradation, ductility, and energy dissipation capacity of the prestressed steel strand-reinforced concrete columns were observed and recorded. The test results show that the failure mode of the prestressed steel strand-reinforced concrete columns is obvious bending failure. Within a certain range of axial compression ratio, the initial stiffness and load-bearing capacity of the specimens increase with the increase in axial compression ratio, but the plastic deformation capacity decreases. Within a certain range of steel strand diameter, the initial stiffness and load-bearing capacity of the specimens also increase with the increase in steel strand diameter, but the ductility coefficient first increases and then decreases. In addition, the seismic performance of prestressed steel strand-reinforced concrete columns was analyzed by the finite element method using DIANA software, and the results were compared with the test results. It was found that the hysteretic curve and stiffness degradation curve obtained from the finite element model are in good agreement with the test results, and the finite element model can accurately study the seismic performance of this type of column. Finally, based on the finite element model, the influence of different parameters on the mechanical properties of the column was discussed.

Computational fluid dynamics study on three‐dimensional polymeric scaffolds to predict wall shear stress using machine learning models for bone tissue engineering applications

AbstractGeometrical patterns and dimensions of the polymeric scaffold play a major role in controlling the degradation and mechanical stimuli for osteogenic differentiation. Wall shear stress (WSS) analysis of scaffold provides a better understanding of the body fluid flow dynamics. A computational fluid dynamics (CFD) study was carried out to understand velocity profile and WSS distribution when the strands are arranged in rectangular and triangular pitch for the different strand diameters and spacing. The number of scaffold surfaces with less than 30 mPa and maximum and average WSS was estimated to check the suitability of the scaffold for loading stem cells. This situation is favorable to induce osteogenic activity and cell viability. Higher spacing/pitch between the strands increases the chances of scaffold surface having WSS less than 30 mPa. When the spacing and diameter are smaller, there is no significant variation in WSS and pressure drop between rectangular and triangular pitch arrangement is observed. Machine learning (ML) models were developed to predict WSS distribution and to reduce the computational cost involved in solving the Navier–Stokes equation. XG Boost and support vector machine (SVM) models outperform the other models in predicting the WSS with high R2 and five‐fold cross‐validation accuracy and are helpful in predicting the optimal design parameters of a three‐dimensional scaffold.

Geometrical and mechanical analysis of polylactic acid and polyvinylidine fluoride scaffolds for bone tissue engineering

Utilising finite element analyses and experimental testing, this study investigates the influence of scaffold porosity on mechanical behaviour and evaluates the potential of polylactic acid (PLA) and polyvinylidine fluoride (PVDF) as bone substitute materials. Scaffold geometries were devised using design parameters adapted from extant literature and then generated using computer-aided engineering tools. Methodical variations in strand thickness were applied, maintaining other design criteria constant for robust analysis. Results, derived under varied loading conditions, suggest that scaffold mechanical properties are influenced significantly by geometry, strand diameter and porosity. Cubic scaffolds exhibited marked strength. Structures with reduced porosity demonstrated heightened mechanical characteristics, while facilitating bone cell proliferation. For a comparative context, PVDF scaffolds were benchmarked against human femur bone properties, revealing a mechanical behaviour alignment, particularly in their Young’s modulus.

Design Evolution of MADMAX Conductor to a Nb–Ti Cable in Copper Conduit

The MADMAX (MAgnetized Disc and Mirror AXion) project aims at detecting axion dark matter in the mass range around 100 μeV. Prerequisite for success is a very large dipole (1.35 m warm bore) with a high magnetic field up to 10 T. A first conductor design made of Nb-Ti Rutherford Cable On Conduit Conductor with a hole in the copper conduit (RCOCC type) was already presented. The coolant is static bath of superfluid helium at 1.8 K. Unfortunately, no conductor manufacturer with an available production line was found to take in charge the cable insertion/soldering process. Actually, such a production line should be compatible with large conductor section (∼400 mm²) including a solder wave device. The type of conductor was changed to use a line developed for ITER Cable In Conduit Conductor (CICC). Nevertheless, the jacket part was kept in copper. The main evolution of the MADMAX conductor design is presently reviewed. The final outer dimensions of the conductor, the void fraction and the required cold work of the copper induces a reverse engineering challenge on the initial shape of the copper profile. Then, the cable geometry modification involves a lots of differences in terms of self-field, strand diameters, transposition paths, joints technique and conductance between the strands and the stabilizer. The mechanical aspects are subject to evolution for the project due to the magnetic design optimization and conductor type change. A sub-modeling approach is used to detail the stress level in the stabilizer jacket. The possibility of wire motion and wire deformation during the conductor compaction in the production line is also discussed. Concerning the thermal analysis, the major difference is the thermo-hydraulic quench back that induces a much higher pressure drop of the helium in the conduit. So, higher pressure induced higher helium velocity and a fast detection after a quench event in superfluid environment becomes possible.

Investigating infant feeding development in wild chimpanzees using stable isotopes of naturally shed hair.

Measuring the relative contributions of milk and non-milk foods in the diets of primate infants is difficult from observations. Stable carbon (δ13 C) and nitrogen (δ15 N) isotopes in hair can be used to physiologically track infant feeding through development, but few wild studies have done so, likely due to the difficulty in collecting hair non-invasively. We assessed infant feeding at different ages in wild chimpanzees (Pan troglodytes) at Ngogo, Uganda using δ13 C and δ15 N of keratin in 164 naturally shed hairs from 29 infants (61 hairs), 6 juveniles (7 hairs), 28 mothers (67 hairs) and 14 adult males (29 hairs). Hairs were collected when they stuck to feces during defecation or from the ground after chimpanzees groomed or rested. We could not distinguish between the hairs of infants and mothers using strand length and diameter. Infants 1-2 years old were most enriched in 13 C and 15 N and showed means of 1.1‰ in δ13 C and 2.1‰ in δ15 N above their mothers. Infants at 2 years had hair δ13 C values like those of their mothers, which suggests infants began relying more heavily on plants around this age. While mother-infant δ13 C and δ15 N differences generally decreased with offspring age, as is expected when infants rely increasingly more on independent foraging through development, milk seemed to remain an important dietary component for infants older than 2.5 years, as evidenced by continuing elevated δ15 N. We showed that stable carbon and nitrogen isotopes in naturally shed hairs can feasibly detect trophic level differences between chimpanzee infants and mothers. Since it can mitigate some of the limitations associated with behavioral and fecal stable isotope data, the use of hair stable isotopes is a useful, non-invasive tool for assessing infant feeding development in wild primates.

Development and optimisation of hydroxyapatite-polyethylene glycol diacrylate hydrogel inks for 3D printing of bone tissue engineered scaffolds

In the event of excessive damage to bone tissue, the self-healing process alone is not sufficient to restore bone integrity. Three-dimensional (3D) printing, as an advanced additive manufacturing technology, can create implantable bone scaffolds with accurate geometry and internal architecture, facilitating bone regeneration. This study aims to develop and optimise hydroxyapatite-polyethylene glycol diacrylate (HA-PEGDA) hydrogel inks for extrusion 3D printing of bone tissue scaffolds. Different concentrations of HA were mixed with PEGDA, and further incorporated with pluronic F127 (PF127) as a sacrificial carrier. PF127 provided good distribution of HA nanoparticle within the scaffolds and improved the rheological requirements of HA-PEGDA inks for extrusion 3D printing without significant reduction in the HA content after its removal. Higher printing pressures and printing rates were needed to generate the same strand diameter when using a higher HA content compared to a lower HA content. Scaffolds with excellent shape fidelity up to 75-layers and high resolution (∼200 µm) with uniform strands were fabricated. Increasing the HA content enhanced the compression strength and decreased the swelling degree and degradation rate of 3D printed HA-PEGDA scaffolds. In addition, the incorporation of HA improved the adhesion and proliferation of human bone mesenchymal stem cells (hBMSCs) onto the scaffolds. 3D printed scaffolds with 2 wt% HA promoted osteogenic differentiation of hBMSCs as confirmed by the expression of alkaline phosphatase activity and calcium deposition. Altogether, the developed HA-PEGDA hydrogel ink has promising potential as a scaffold material for bone tissue regeneration, with excellent shape fidelity and the ability to promote osteogenic differentiation of hBMSCs.

Transcriptome Changes Reveal the Toxic Mechanism of Cadmium and Lead Combined Exposure on Silk Production and Web-Weaving Behavior of Spider A. ventricosus.

The combined exposure of multiple metals imposes a substantial burden on the ecophysiological functions in organisms; however, the precise mechanism(s) remains largely unknown. Here, adult female A. ventricosus were exposed to single and combined exposure to cadmium (Cd) and lead (Pb) through the food chain. The aim was to explore the combined toxicity of these metals on silk production and web-weaving behavior at physiological, cellular morphological, and transcriptomic levels. The Cd and Pb combined exposure significantly inhibited the ability of silk production and web-weaving, including reduced silk fiber weight and diameter of single strands, lowered weaving position, induced nocturnal weaving, and increased instances of no-web, and showed a dose-response relationship on the Cd and Pb bioaccumulation. Concurrently, severe oxidative stress and degenerative changes in cells were observed. In addition, the combined pollution of Cd and Pb demonstrated synergistic effects, influenced by variations in concentration, on the enrichment of metals, inhibition of silk weight, oxidative damage, and cellular degeneration. At the transcriptome level, the upregulated ampullate spidroin genes and downregulated amino acid anabolic genes, upregulated Far genes and downregulated cytoskeleton-related TUBA genes, and overexpressed AChE and Glu genes may tend to present promising potential as biomarkers for silk protein synthesis, cellular degeneration, and neurotransmitter induction. This study offers an enormous capability for a comprehensive understanding of the eco-toxicological effects and mechanisms of multiheavy metals pollution.

In vitro evaluation of polycaprolactone‐based structure for guiding segmental bone defect

AbstractSegmental bone tissue engineering is a highly effective approach for the repair of large bone defects. In this article, 3D printing was used to fabricate the polycaprolactone (PCL)/NaCl‐based cylindrical structures. The effects of the structure's thickness (L) and NaCl concentration on the mechanical properties, degradability, swelling behavior, porosity, and cytotoxicity of the samples were investigated. Response surface methodology was employed to study the mechanical behavior using the central composite design (CCD). Results showed that increasing the NaCl concentration up to 10% wt significantly improved the degradability, swelling, and hydrophilicity of the structures. It was also indicated that the maximum stiffness of the guide structures under vertical loading was almost five times larger than the horizontal loading direction, but the samples showed greater compressive strength and elongation under horizontal compressive loading. Results indicated that the mechanical properties of the structures were more dependent on the structure thickness so the thicker structures with an 800 μm thickness had better mechanical properties in both vertical and horizontal loading. Cytotoxicity assay also approved the nontoxic effect of the PCL structures on the MC3T3 osteoblast cell line. Based on the results, the PCL‐based structures were a suitable candidate to act as a guide for segmental bone tissue engineering.Highlights A 3D‐printed conduit was manufactured to guide bone reconstruction Response surface methodology (RSM) using central composite design (CCD) was employed NaCl concentration and the diameter of strands were the main parameters This 3D‐printed guiding approach is useful for segmental bone tissue engineering

Numerical Investigation of Cracks at Girder Ends of Prefabricated Post-Tensioned Prestressed Concrete I-Girders

Prefabricated post-tensioned prestressed concrete (PTC) girders with high degrees of prestressing have been developed continuously in recent bridge designs to reach longer spans, higher quality, and larger load-bearing capacity. However, during the prefabrication process, several inclined and horizontal cracks were observed at the ends of a new style post-tensioned concrete girder, which could have a negative impact on the girders' longevity. In this study, a nonlinear finite element analysis technique was utilized to illustrate how concrete reacts and the mechanisms behind typical cracking patterns during the actual post-tensioning sequence. The prestressing load of a PTC girder was simulated with an improved cooling temperature method that accounts for immediate prestress losses. The field of principle tensile strain patterns and primary strain trajectories explained the overall mechanism underlying typical cracking behaviors. The results showed that the horizontal cracks under the anchorage plate (behavior 1) were generated by the bursting force, whereas the inclined cracks (behavior 2) and the horizontal cracks between the strands N1 and N2 anchor plates (behavior 3) were caused due to the spalling force. The effects of self-weight, girder end forms, as well as the transfer length of the prestressing strands, were discussed. The result demonstrates that both the self-weight and girder end shapes have a considerable effect on the behaviors of the anchorage zone. It is suggested that the transfer length of the anchor head be greater than 26 times of strand diameter to achieve the same effective stresses as the theoretical values.

A Comprehensive Investigation of Winding Eddy and Circulating Current Losses of Stator Iron Coreless PMBLDC Motors

A method is proposed to comprehensively study the eddy and circulating current losses of stator winding wound by multiple parallel strands, to further improve the power density of stator iron coreless permanent magnet brushless DC (PMBLDC) motors. Analytical models of the eddy and circulating current losses in stator winding are deduced firstly to explicitly express the influencing factors of these two losses. As is shown, these factors are mutually contradicting. While the eddy current loss can be greatly reduced by using multiple parallel conductor strands, the circulating current loss will be extensively increased. The factors influencing these two winding losses, such as the strand diameter, magnetization types, and rotating speed, are investigated. A prototype of stator iron coreless PMBLDC motor without an inner rotor core is manufactured and tested to validate the theory. The experimental results of winding eddy and circulating current losses with different combinations of strand diameters and parallel numbers agree well with the theoretical results.

Fabrication of polycaprolactone/chitosan/hydroxyapatite structure to improve the mechanical behavior of the hydrogel‐based scaffolds for bone tissue engineering: Biscaffold approach

AbstractThe main idea of this study is to create a 3D printed scaffold to improve the mechanical behavior of hydrogels for bone tissue engineering. This paper investigated the effects of infill percentage and strand diameter on the 3D printed polycaprolactone/Chitosan/HA scaffold's mechanical properties. The printing parameters were optimized by central composite design in response surface methodology. The X, Y, and Z axes measured stiffness (N/m), compressive strength (MPa), and elongation at break (%). The results showed that the highest stiffness of all samples (in both vertical (65 MPa) and horizontal (32 MPa) loading dimensions) could be found in the scaffolds with 40% infill and the strands with 400 μm diameter. It was also indicated that the degradability of the samples could be improved (0.33%–1.03%) with a reduction of strand diameter from 600 to 400 μm. The most swelling was attributed to the scaffold with 50% infill and strand diameter of 600 μm. Hydrophilicity was improved by employing chitosan (78.3°–66.3°). Results depicted good biocompatibility (>80%) of the samples. To sum up, the idea of a biscaffold with suitable engineering can be a good idea to enhance the mechanical behavior of hydrogel‐based scaffolds.

An analytical study of precast, prestressed concrete girder spans using 0.7 in. strand

It has been proposed that 0.7 in. (17.8 mm) diameter prestressing strand be permitted for use in bridge girders. If 0.6 in. (15.2 mm) diameter strand is replaced on a one-to-one basis with 0.7 in. strand, the pretensioning force can be increased by 35%. When designs use 0.7 in. strands as well as high concrete strengths, longer-span prestressed concrete girders may be achieved. An extensive analytical study is presented to assess the maximum girder span lengths that can be achieved when using 0.6 and 0.7 in. strands. A parametric design study with 584 cases was conducted to examine the influence of girder shape and size on the potential benefits of using 0.7 in. strands. A detailed finite element analysis of some of the longer spans achieved was also conducted. The impacts of using 0.7 in. strands on end-region detailing requirements, prestress transfer, and handling and erection stability of long-span girders were examined. Girder span increases of up to 22% were achieved using 0.7 in. strand in place of 0.6 in. strand. The larger pretension forces affected end-region detailing and increased congestion, though all resulting requirements were constructible. The longer spans affected girder stability calculations, and some girder types required a wider top flange to meet stability-related limit states.