Yousif A. Mansoor

The corrosion is a serious problem of construction projects that affect structural durability. The effect of corroded stirrups at the behaviour of reinforced concrete beams especially on ultimate shear strength and ductility was investigated in this study. Eight specimens of reinforced concrete beams were tested with four-point loading until failure. The dimensions of the specimen were 150 mm wide, 200 mm high and 1200 mm long. Six specimens were accelerated through an electrochemical process. The main variables of this study were the stirrups diameter and corrosion level. The results concluded that the stiffness and strength reduced in corroded beams when compere with control specimens. This reduction exhibited to increase with the level of mass loss in stirrups and a smaller diameter of stirrups. In addition to that, the ductility index trended to reduce from 118% to 68% for groups A (Ø6 @ 200 mm c/c); while from 68% to 35% for group B (Ø8 @ 150 mm c/c) which indicates that brittleness of beams raised. At high corrosion level, failure modes may change from shear-compression failure to rupture of stirrups.

The last two decades have seen a growing in the reinforced concrete bridges that need to maintain in in Al- Anbar governorate, Iraq due to the wars. In terms of safety periodic inspection for the damages plays a critical role in the maintenance of reinforced concrete bridges. However, some of testing technologies and techniques that used by periodic inspection cannot be done visually due to their complexity. Several attempts have been made to use the Knowledge-Based Systems (KBS) as an alternative system to evaluate the damages in the structural parts of the reinforced concrete bridges visually. The main aim of this study is to develop an alternative system to assess the damages in the structural parts of the reinforced concrete bridges. This study develops an inspection system for damaging concrete bridge (ISDCB) as an evaluation system to assess the damages in Palestine bridge in Al-Anbar governorate, Iraq. The proposed system shows a good ability to give an easy, fast and suitable answers to maintain the main parts in the reinforced concrete bridges.

The main cause of ageing damage in reinforced concrete structures is reinforcement corrosion. Damage can be detected visually as coincident cracks along the reinforcement bar, which are significant of both reduction of the re-bar, cross-section and loss of bond strength for reinforced concrete. The reinforced concrete is one of the most widely used engineering materials as final lining of tunnels. The corrosion is common durability problems that have significant effect on the tunnel performance. This study intends to analysis reinforcement concrete corrosion at the tunnel lining by applying temperature expansion theory on steel through numerical simulation process, with expansive force effect. The thickness of concrete cover and the diameter of steel bar have an impact on the stress for reinforcement concrete during propagation of corrosion process. The corrosion cracks appear at the corner of a tunnel lining then in invert and vault because the maximum stress will be in the corner then in invert and vault. The internal force in the concrete lining changes differently when the corrosion rate change.

The main idea of this study is to evaluate the bond strength for reinforcing concrete with corrosion that it can damage the R.C bond. Pullout tests carried out to evaluate the effects of corrosion on bond, for that purpose a series of specimens with varying reinforcement corrosion levels tested. The acceleration steel corrosion was 4, 6 and 8 days corrosion. The aim of choosing 4, 6 and 8 days that are trying to reflect field condition on test. The test designed to provide the data required to assess the bond properties with different variables, bar diameter and concrete strength. The pullout test specimen was designed to can get best significant result by provided anchored length and avoid yield failure. The test result shows verity relation between the bond strength and corrosion. The percentage of steel metal loss was smaller for a large diameter bar compared to that for smaller diameter bar at a constant corrosion rate. For C30-10 results show there are reduction with bond strength around 22% for 4 days corrosion, 25% for 6 days corrosion and 31% for eight days corrosion. While for C30-14 results show there are reduction with bond strength around 19% for 4 days corrosion, 23% for 6 days corrosion and 28% for 8 days corrosion.

Over the last several years, many concrete tunnels have been constructed for roads, highways, and railways. For safety in concrete tunnel, periodic inspection has been conducted using many testing technologies and techniques. However, these technologies cannot replace visual inspection because of their slow and complicated procedures. For this reason, the Knowledge-Based Systems (KBS) are used to diagnose R.C tunnel lining crack damage (DICRCTL). In this paper, we attempt to propose an alternative to the human expert, to give technical decisions in diagnosing crack damages in second segment of R.C. tunnel lining. To overcome this requirement, an expert system is developed to achieve the research aim. This proposed system was constructed on a knowledge base that incorporates with the gathered information in the form of rules which is suitable to implement in an expert system environment to diagnostic advisory nature. The proposed application results show an easy, fast and satisfactory answer to engineering needs.

The intersection is an important part of the highway system. The operational efficiency, capacity, safety and cost of the system depended on design of roundabout intersection, especially in the urban area. The present study include analysis, evaluation and improvement of traffic operation for selecting roundabout, Kahtan Square (KS) in Baghdad city by using many alternatives under local exist conditions and found best proposal to enhance the performance at the required facility. To achieve these objectives, SIDRA traffic program is used for traffic analysis process. It has been concluded that, fly over at the main path of traffic movement at KS (Baya'a—Yarmok hospital) is the best proposal to improve the capacity and traffic operation for KS.