Torsional Behavior of RC beams Strengthened by Near Surface Mounted-Steel Wire Rope Under Repeated Loading

In this paper, the torsional behavior of strengthened beams, which were subjected to constant and incremental repeated loads is studied. Repeated loads have a negative effect on the strength of beams as they reduce the beams resistance to external loads. External strengthening is usually used to increase the strength of beams for different applied loading. The near-surface mounted technique is a type of strengthening recently used to improve the strength of beams. The experimental program includes testing of twelve beams. All beams have the same dimensions and the same reinforcement. Nine of those beams are strengthened with different configurations of steel wire rope, and three beams are non-strengthened (reference beams). The results show that the decreasing of the spacing between wires (increasing the amount of steel wires) leads to an increase in the beam torsion strength and a decrease in the twist angle of beams. All strengthened beams show high resistance to the repeated load, especially constant repeated load, the increased torsional capacity has reached to 181.12% in beams under constant repeated load compared to the related beam subjected to monotonic load

Impact of opioid-free analgesia on pain severity and patient satisfaction after discharge from surgery: multispecialty, prospective cohort study in 25 countries

Background: Balancing opioid stewardship and the need for adequate analgesia following discharge after surgery is challenging. This study aimed to compare the outcomes for patients discharged with opioid versus opioid-free analgesia after common surgical procedures.Methods: This international, multicentre, prospective cohort study collected data from patients undergoing common acute and elective general surgical, urological, gynaecological, and orthopaedic procedures. The primary outcomes were patient-reported time in severe pain measured on a numerical analogue scale from 0 to 100% and patient-reported satisfaction with pain relief during the first week following discharge. Data were collected by in-hospital chart review and patient telephone interview 1 week after discharge.Results: The study recruited 4273 patients from 144 centres in 25 countries; 1311 patients (30.7%) were prescribed opioid analgesia at discharge. Patients reported being in severe pain for 10 (i.q.r. 1-30)% of the first week after discharge and rated satisfaction with analgesia as 90 (i.q.r. 80-100) of 100. After adjustment for confounders, opioid analgesia on discharge was independently associated with increased pain severity (risk ratio 1.52, 95% c.i. 1.31 to 1.76; P < 0.001) and re-presentation to healthcare providers owing to side-effects of medication (OR 2.38, 95% c.i. 1.36 to 4.17; P = 0.004), but not with satisfaction with analgesia (beta coefficient 0.92, 95% c.i. -1.52 to 3.36; P = 0.468) compared with opioid-free analgesia. Although opioid prescribing varied greatly between high-income and low- and middle-income countries, patient-reported outcomes did not.Conclusion: Opioid analgesia prescription on surgical discharge is associated with a higher risk of re-presentation owing to side-effects of medication and increased patient-reported pain, but not with changes in patient-reported satisfaction. Opioid-free discharge analgesia should be adopted routinely

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Strength of Reinforced Reactive Powder Concrete Hollow Beams

The main objective of this research is to investigate the structural behavior and strength of reinforced reactive powder concrete beams with a hollow section subjected under two point concentrated loading. The experimental work consist of ten beams with dimensions (150mm width×200mm height×1000 mm length), eight of them are hollow beams and two solid beams were cast and tested up to failure. The major parameters adopted in the current research includes the hollowness ratio (10% and15%), hollow location (at top or at bottom), and hollow shape (circle or square). The amount of longitudinal and transverse reinforcement, concrete strength and the other parameters were kept constant for all the specimens. The comparisons between all specimens (hollow and solid) are based on the load carrying capacity, deflection, crack pattern and mode of failures. Results showed that the strength capacity of hollow beam when the hollow lies in the bottom is much higher than for top hollow, and the square hollow will lead to more decrease in the beam strength compared with the circular hollow and this is more evident when the hollowness ratio increases from (10% to 15%)

Repairing of Reactive Powder Concrete T-Beams Containing Web Opening by CFRP Strips

In modern buildings, transverse openings are often used beams for the purpose of supplying and service pipes. Due to the presence of the openings in the concrete beams lead to the formation of cracks around the openings due to the stresses concentration in a small area above and below of the opening. The repairing, maintenance, and upgrading of structural members, are maybe one of the most pivotal problems in civil engineering applications. In this research, an experimental work is conducted to study the behavior of the reinforced RPC T-beams that containing openings and repair this beams using CFRP strips. The Experimental program of the present study includes two parts, the first part includes testing of seven reinforced reactive powder concrete RPC T-beams, which casted and tested, one beam is without opening as a reference beam and the rest, were provided with an opening. and these beams are divided into two groups. The first group was used to study the effect of the openings shape (circular and square) and the second group was used to study the effect of the openings locations, which consists three locations (Lc/2, Lc/3 and Lc/4). These are measured from the support center to the openings center. While the second part including a repaired all beams in the first part the using carbon fiber polymer. The test results indicated that the presence of openings in the beams web caused a reduction in the reinforced RPC T-beams ultimate load carrying capacity with about (10-55)%, Also lead to increasing in deflection compared to control beam before repairing at same loading. Studying the shape effect showed that the beams with square openings have average ultimate load carrying capacity lower by 36% compared with the control beams. While beams with containing circular openings have average ultimate load carrying capacity lower 29%. From the test results, it could be concluded that the presence of the openings in the shear region led to a decrease in ultimate load carrying capacity a about 38% to 49% for opening of opening at (Lc/3 and Lc/4) respectively. While the presence of openings in the flexural region led to a decrease in the ultimate load carrying capacity rate of 11%. Related to the repairing study part it was found that the average ultimate load carrying capacity for repairing beams was 103% compared with the not repaired beams

The Assessment of Using CFRP to Enhance the Behavior of High Strength Reinforced Concrete Corbels

In this research, an experimental study is conducted to investigate the behavior and strength of high strength reinforced concrete corbels externally bonded with CFRP fabric sheets and Plates with different patterns taking into account the effect of adopted variables in enhancing the ultimate strength; the effect of shear span to effective depth (a/d), configuration, type and amount of bonding. Eleven high strength reinforced corbels were cast and tested under vertical loads. Test results showed there was an improvement in the behavior and load carrying capacity of all strengthened corbels. An increasing in the ultimate strength of strengthened corbel by inclined CFRP strips reached to (92.1%) while the increasing reached to (84.21%) for using one horizontal CFRP Plates compared to un-strengthened reference specimen. Also, it can be conducted that the increase of (a/d) ratio from (0.6 to 0.8) resulted in decreasing by 21.05% in ultimate load capacity of corbels and from (0.4 to 0.6) by 31.25% and 58.69% in cracking and ultimate loads respectively

Developing Porous Concrete Interlocking Pavement Blocks Utilizing Recycled Concrete Aggregate for Rainfall Harvesting Use

Rainwater harvesting and flood prevention in cities are significant urban hydrological concerns. The use of porous pavement is one of the most effective solutions to handle this matter. Thus, this study aims to develop Porous Interlocking Concrete Pavement (PICP) using recycled aggregate from concrete waste. This porous pavement, then later, can be utilized in low traffic areas and parking lots to harvest water by infiltration and reduce surface runoff. First, the physical properties of the porous concrete blocks, such as density (unit weight), absorption, coefficient of permeability, and porosity, were studied. Also, the mechanical properties of concrete mixtures like compressive strength and flexural strength were tested. This study used two types of PICP, the first one with ordinary coarse aggregate (P1) and the second with recycled crushed concrete coarse aggregate (P2), and then compared their performance to the conventional concrete pavement blocks used the two types of coarse aggregate (R1 and R2). The results show that the unit weight (density) of porous types was reduced by 25% and 26%, and the total porosity increases by around 2.4 times and 18 times respectively, as compared to conventional concrete pavement types. However, the compressive strength and flexural strength of porous concrete types decreased by (55% and 71%), respectively, compared to conventional types. Overall, the infiltration test results showed that the infiltrated water through porous concrete increased by about 83% in comparison to conventional concrete. From the results, utilizing porous concrete pavement can be considered a promising material in terms of water harvesting and decreasing rainwater flooding. Additionally, using recycled concrete can bring economical and environmental benefits

The Effect of Opening Size and Location on the Performance of Reinforced Concrete T-Beams under Pure Torque

IN modern buildings, transverse openings are often used in order to pass the pipes of health services, electrical cables or air conditioning ducts and other prepuce. The presence of these openings leads to a weakening of the beam so it must work to investigate the behavior of these beams in order to know how the presence of openings affects beam resistance. In this research, the behavior of reinforced concrete T-beams with circular openings exposed to pure torsional moment is studied. The experimental program involves testing of five beams with same dimensions and reinforcements. One of them is solid beam and used as reference for comparison with other beams with an opening and the other four T- beams containing circular openings of deferent dimension(100 and 150) and location(Lc/2 and Lc/3). Practical results show that the T-beam with circular openings of diameter (100mm) with different locations (Lc/2 and Lc/3), where Lc is the clear span of the beam, have an ultimate torsional capacity lower than that for solid beam by about (23% and 30%) respectively. The increase of the openings size causes a significant decrease in torsional capacity, where the beams with circular openings of diameter (150mm) with different locations (Lc/2 and Lc/3) have an ultimate torsional capacity lower than that for solid beam by about (56 % and 61%) respectively. Practical results show also that the presence of circular openings with diameter of 47% and 71% from the total depth increases the angle of twist significantly as compared with reference beam for the same applied torque level

Torsional Behavior of RC Beams with Transverse Openings Strengthened by Near Surface Mounted-Steel Wire Rope Subjected to Repeated Loading

The presence of the openings negatively effects on the strength of the beams where they act as a weak point because of the sudden change in the cross-section of the beam, so it becomes necessary to make strengthening for the beams to resist the effect of the openings and improve the strength of the beams, especially if the beams are subjected to repeated loads because of its effect on the strength at the failure. This paper studies the effect of the openings on the beams subjected to repeated loading and determine the extent of the increase in the strength of the beams when strengthened by the NSM technique. The experimental program included casting and testing fifteen RC beams, six of them considered as a control beams (three with strengthening and three without strengthening), and nine of them having circular transverse openings in different locations and strengthened by the NSM technique. Every type of beams is tested under three different types of loads (monotonic, constant repeated load, and incremental repeated load). All of the beams have the same dimensions and same reinforcement. The results show that all the beams with transverse openings are affected by repeated loads where the ultimate torque decreases and the twist angle increases. The existence of openings has a noted effect on reducing the ultimate torque, whereas the percentage of decrease in the ultimate torsional capacity reached 43.83% at the beam where the opening location is closest to the support (at the quarter of the clear span) and subjected to constant repeated loads, and the ultimate torque is significantly improved when the opening position is moved away from the supports. Also, the existence of strengthening reduced or eliminated the influence of openings on the ultimate torque compared with related non- strengthened beams

Behavior of Reinforced Concrete Corbels Strengthened with CFRP Strips Subjected to Monotonic and Repeated Loading

Concrete corbels are short cantilevers subjected to monotonic and repeated loads. Repeated loads generally negatively affect the concrete structural members' strength as they decrease the resistance to external loads. To increase these loads, strengthening with carbon fiber reinforced polymer (CFRP) strips as an externally bounded technique is used. This paper studies the behavior and strength of strengthened corbels subjected to monotonic and repeated (constant and incremental) loads. The experimental program included the casting and testing of twelve double-concrete corbels. All specimens have been kept constant for corbel dimensions and main and secondary reinforcement. Nine were strengthened with CFRP strips using different patterns, while the others were left un-strengthened as control corbels. The results showed that both repeated loads' types, i.e., constant and incremental, affected the ultimate load capacity of corbels. Compared to monotonic loading, a reduction occurred in ultimate load and ultimate deflection for corbels subjected to five repeated loading cycles. For corbels strengthened by externally bounded CFRP strips under any applied loads, the ultimate load significantly increased, while the ultimate deflection decreased compared to un-strengthened at the same applied load. All corbels failed by de-bonding the CFRP strips