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Concrete-filled double-tube (CFDT) columns are a new idea in designing and building structures. In this manuscript, the effect of various parameters (yield stress of the steel tube, the characteristic strength of concrete, the arrangement of steel tubes, and the ratio of the diameter to the thickness of the steel tubes) on the bearing capacity of eccentrically loaded CFDT columns is studied for the first time. Using ABAQUS software, the finite element model is validated based on available laboratory specimens. The bearing capacity of eccentrically loaded CFDT columns with different material and mechanical specifications is compared in the form of P-M diagrams. The results show that by increasing the yield stress of the outer tube, increasing the diameter of the outer tube and increasing the strength of the outer concrete, the bearing capacity of the CFDT column is increased. Based on the failure modes of the CFDT column under the eccentric load, the outer concrete has the most damage in the tension and compression mode. In addition, the ductility and energy absorption capacity are compared between the CFDT and the concrete-filled steel tube (CFST) columns. Based on this comparison, the performance of the CFDT column is better under eccentric loading. Finally, a formula for designing and determining the bearing capacity of eccentrically loaded CFDT columns is proposed. In the last part of the work, the seismic performance of multi-story buildings equipped with the CFDT and CFST columns under a real earthquake is examined. In terms of seismic performance, the frames equipped with the CFDT columns have more energy absorption and base shear than the frames equipped with the CFST columns. Also, the displacement of the roof related to the bending frame with CFDT columns is less than the frame with CFST columns. The results indicate that CFDT columns improve the seismic performance of tall buildings.

Distal radial fractures represent one of the most common fractures in children with the majority treated by closed reduction and cast application. Redisplacement after manipulation can occur resulting in potential poor outcome. We performed a prospective study of children undergoing closed reduction of distal radial fracture and evaluated a range of possible risk factors contributing to loss of reduction.

Introduction: Life-threatening hemorrhage associated with low-energy pelvic fracture has been described in single cases in the literature. However, there is limited evidence available on the bleeding risk associated with hemodynamically stable osteoporotic pelvic fractures. The objective of this study was to estimate the bleeding risk associated with low-energy osteoporotic pelvic fractures in the elderly population.Materials and Methods: A retrospective review of patients aged > 65 years old with pelvic fractures admitted between 2015 and 2018 was performed. Eighty-two patients were identified: 12 males and 70 females with a median age of 86 years. The median Charlson comorbidity index was 6 (interquartile range = 5-7). Eighty-one fractures were classified as lateral compression I or Tile A2, and 1 fracture was classified as lateral compression II or Tile B2. Forty patients were on concurrent anticoagulation treatment. In 4 patients on warfarin, this treatment was reversed on admission.Results: The mean hemoglobin (Hb) level on arrival was 12.36 g/dL (±1.67 g/dL). There were significant drops in Hb levels on day 1 (Hb = 11.22 ± 1.86 g/dL, P< .001) and day 4 (Hb = 10.97 ± 1.6 g/dL, P< .001). Nine percent of patients required a blood transfusion. The mean baseline Hb level pre-transfusion was 8.33 g/dL (±1.15). Preexisting anticoagulation treatment did not predispose patients to greater decreases in Hb levels on day 1 (mean difference = 0.16 g/dL, P= .62) or day 4 (mean difference = 0.29 g/dL, P= .48) post-admission.Discussion: An observed mean decrease in Hb level of up to 1.4 g/dL can occur in hemodynamically stable elderly patients with osteoporotic pelvic fractures, reflecting an approximate loss of 1.4 units of packed red blood cells.Conclusion: This degree of decrease in Hb may be clinically significant in geriatric patients with chronic anemia and a history of cardiovascular disease.