High modulus carbon fiber materials for retrofit of steel structures and bridges
This paper summarizes the research work dealing with the use of high modulus carbon fiber reinforced polymer (HM CFRP) materials for the retrofit of steel structures and bridges. The research work included selection of an appropriate adhesive for bonding HM CFRP materials to steel and the performance of Large-scale steel-concrete composite beams tested to examine the behavior of different strengthening schemes. The research findings demonstrate the effectiveness of the proposed HM CFRP strengthening system.
REHABILITATION OF STEEL BRIDGE GIRDERS THROUGH THE APPLICATION OF ADVANCED COMPOSITE MATERIALS
This Innovations Deserving Exploratory Analysis (IDEA) project evaluated the feasibility of using advanced composite materials in the rehabilitation of deteriorated steel bridge members. The primary cause of such deterioration is loss of steel due to corrosion. Due to various conditions that accelerate corrosion, such as debris accumulation, the bottom flanges of girders are usually the site of the largest corrosion. The flexural characteristics of steel bridge girders are shown to be improved through the application of various repair schemes to the bottom flange. This investigation focused on the case of single span girders where the bottom flange is subjected to tensile stresses. The composite rehabilitations are attached to the corroded steel member using adhesive bonding; therefore, the durability of the adhesive bond under the various conditions that are present in the field over time is a critical issue. Durability tests were performed on a number of adhesives to determine the effect of the environmental conditions on the fracture toughness of the bond over time. Rehabilitation schemes were developed and tested for a variety of field conditions. One of the schemes was used to rehabilitate girders taken out of service in Pennsylvania due to excessive corrosion. This provided an opportunity for the process to be applied to a member of realistic size and with corrosion as exists in the national bridge inventory.
Complications of motility peg placement for porous hydroxyapatite orbital implants
Aim: To evaluate the complications associated with pegging of porous hydroxyapatite orbital implants. Methods: Complications associated with pegging were retrospectively reviewed from the charts of 100 of 133 patients with hydroxyapatite implantation from 1993 to 2000. Results: 48 (48%) of the 100 hydroxyapatite implanted patients who had undergone pegging were found to have problems with their pegs, including discharge (45.8%), peg falling out (20.8%), pyogenic granulomas (16.7%), popping peg (14.6%), hydroxyapatite visible around peg hole (8.3%), part of peg shaft visible (6.2%), peg drilled off centre (6.2%), peg drilled at an angle (4.2%), and excess movement of peg (4.2%). The standard peg fell out statistically more often than the peg and sleeve system (Yates's corrected χ2, p=0.038). There was a trend towards complications of the peg with use of a standard peg (versus sleeved peg) (p=0.226). Conclusions: There are several potential complications of pegging. Most complications are minor and can be managed successfully.