Static Analysis of Reinforced Concrete Pipe Strengthened with GFRP Laminates
This paper presents a study of reinforced concrete pipe with the application of continuous glass fiber reinforced polymer sheet (GFRP). The pipe material is considered to be composed of reinforced concrete and the pipe is strengthen by using glass fiber reinforced polymer sheet. The reinforced concrete pipe is analyzed with different layers of externally applied GFRP sheet. Analysis is carried out in commercially available ANSYS software. A finite element model is developed for the pipe wherein the material properties as mentioned are used. The solid 186 layered structural solid element has been used for discretization of the model. Two sets of GFRP sheets (4 layer & 8 Layer) were considered for the analysis. Results obtained were compared with the controlled pipe made up of reinforced concrete. Results are presented for simply supported boundary conditions for the pipe. The deformation and stress distribution across the pipe has also been analyzed
Durability characteristics of concrete beams externally bonded with FRP composite sheets
Abstract The strengthening of concrete structures in situ with externally bonded fiber reinforced plastic (FRP) composite sheets is increasingly being used for repair and rehabilitation of existing structures. This paper provides information in the area of long-term durability of concrete beams externally bonded with FRP sheets. It was intended to study the effect of harsh environmental conditions such as wet/dry cycling using salt water on the performance of FRP-bonded concrete beams and on the interfacial bond between the fiber and the concrete. Concrete beams were strengthened with four different types of FRP sheet: two carbon and two glass. Three different types of two-part epoxy were used. Test variables included (1) the type of fiber, (2) the type of epoxy system, and (3) the environmental exposure condition. The specimens were conditioned in two different environments: (a) room temperature (+20 °C), and (b) 300 wet/dry cycles (salt water was used for the wet cycles and hot air at 35 °C and 90% humidity for the dry). At the end of each exposure, load-deflection curves of the specimens were obtained in order to evaluate their maximum capacity, stiffness, and ductility. The performance of the wet/dry exposed specimens was compared with those kept at room temperature. Results showed that specimens subjected to wet/ dry environmental conditions and those kept at room temperature exhibited significant improvement in flexural strength when FRP sheets were bonded to the tension face of the concrete beams. However, the specimens subjected to wet/dry conditions showed less improvement than those kept at room temperature. None of the specimens failed due to FRP rupture but rather due to the debonding between the FRP sheet and the concrete interface. The selection of epoxy was shown to be very important for using the FRP strengthening technique, especially in a marine environment.
Suitability and water quality criteria of an open drainage municipal sewage water at Coimbatore, used for irrigation.
Sanganur canal is the major open drainage system which has intricate linkage with storm water supply, domestic sewage and industrial effluent disposal. Water samples from various stations were collected and analysed for physicochemical parameters to assess the water quality of the Sanganur canal system. The study revealed that physicochemical parameters like pH, EC, TDS, DO, BOD, COD exceeded the permissible limit, clearly indicating the need of proper treatment of waste water before discharge into the Noyyal river.