Aged highway bridges have become substantially prevalent in recent years. Moreover, combined deterioration, caused by using deicing agents in winter, has led to increased bridge maintenance costs. Accordingly, to extend the service life of bridge decks, this study utilized actual inspection data and major deterioration factors to derive the remaining service life of bridge decks. Based on this study, the following three factors are selected: deicing agent exposure grade, pavement condition state, and surface improvement status. Performance degradation curves were derived for 11 cases that considered the representative three deterioration factors, and the performance degradation of decks was examined for each deterioration factor. Additionally, a process to determine maintenance priorities, using the current condition of highway bridges and the deterioration factors of individual bridges, was proposed. The maintenance demand was predicted based on the end of deck life, which indicated that the demand for deck replacement will sharply increase in 15 years, and that the decks of more than 2000 bridges will reach the end of life in 40 years. Furthermore, this paper proposes a process for prioritizing the maintenance of approximately 9000 highway bridge decks. By applying the prioritization process for bridge deck maintenance to the bridge deck, not only can the life of the bridge deck be extended, but also environmental pollution can be minimized. Additionally, an optimizing design for bridge decks, by considering the remaining life and deterioration factors, can be possible. Therefore, it is expected that the sustainability of the bridge deck can be accomplished.

Noise and vibration caused by pile driving may disturb surrounding areas to the extent that nearby residents and businesses may file civil complaints, which can bring construction to a halt. To overcome these issues, construction engineers have worked diligently to develop low-noise and low-vibration pile driving methods. One such method, involving noise-free and vibration-free pretensioned spun high-strength concrete (PHC) screw piles, is proposed in this paper. This pile driving method penetrates the ground by rotating and compressing the pile to minimize noise and vibration in addition to maximizing capacity. A noise-free and vibration-free PHC screw pile prototype, the first of its kind, was manufactured and subjected to two pilot tests to determine its production and construction requirements in addition to its performance. In pilot tests, the new noise-free and vibration-free PHC screw pile driving method was found to successfully reduce noise and vibration compared with pile driving involvi...

Modern methods for designing drilled shafts in soft rock require knowledge of the compressive strength and modulus of the rock. However, rock jointing at many sites prohibits the recovery of samples of sufficient length and integrity to test rock cores in either unconfined or triaxial compression tests. Since rational design procedures usually require values of compressive strength, surrogate methods must be employed to estimate the compressive strength of the rock. The surrogate methods considered in this study was Texas cone penetrometer tests, and performed at several sites in North Central Texas. In order to develop the relationships between Texas cone penetrations and side and base resistances of rock socketed drilled shafts, three field load tests were conducted. Based on the field study and literature reviews, a relationship between Texas cone penetration tests and axial resistances of rock socketed drilled shafts was proposed.

Movements and lateral earth pressure of integral abutment bridges are mainly affected by seasonal thermal variations. To investigate this aspect, a test bridge was constructed with integral abutments as stub type abutments founded on flexible piles, and abutment movement, earth pressure, and thermal exchange were monitored from 2000 to 2002. Based on long-term monitoring of the test bridge, several relationships for integral abutments, which are the relationships between abutment movement and thermal exchange, abutment movement and earth pressure, and earth pressure and thermal exchange, were proposed. In addition, a three-dimensional finite-element study was conducted to verify the moving behavior of the integral abutment, and its results showed that the integral abutment had rotated and laterally displaced.