The accurate measurement of diverse displacements of structures is an important index for the evaluation of a structure’s safety. In this study, a comparative analysis was conducted to determine the integrated RTK-GPS/accelerometer method that can provide the most precise structure displacement measurements. For this purpose, three methods of calculating the dynamic displacements from the acceleration data were comparatively analyzed. In addition, two methods of determining dynamic, static, and quasi-static displacements by integrating the displacements measured from the RTK-GPS system and the accelerometer were also comparatively analyzed. To ensure precise comparison results, a cantilever beam was manufactured onto which diverse types of displacements were generated to evaluate the measurement accuracy by method. Linear variable differential transformer (LVDT) measurements were used as references for the evaluation to ensure accuracy. The study results showed that the most suitable method of measuring the dynamic displacement with the accelerometer was to calculate the displacement by filtering and double-integrating the acceleration data using the FIR band-pass filter. The integration method that uses frequency-based displacement extraction was most appropriate for the integrated RTK-GPS/accelerometer method of comprehensively measuring the dynamic, static, and quasi-static displacements.

In this study, the effects of curing temperature and curing time on the mechanical properties of polysulfide polymer concrete were investigated. For this purpose, several laboratory tests were conducted to measure the compressive, flexural, and bond strengths of the concrete. The ranges of curing temperature and curing time considered were −10–60 °C and 3–672 h (28 days), respectively. The test results show that a curing temperature above 20 °C adversely affects the strength of the concrete. Regression equations derived from the test results demonstrate the reliability of the results for the estimation of flexural and bond strengths from a given value of compressive strength.

The use of precast concrete modular construction in the replacement and rebuilding of old structures has recently increased. However, the joints between modules in this type of construction exhibit special behavior that should be considered when analyzing the behavior of modular members. Both stability and serviceability should be studied; however, existing research has only addressed the former. Research regarding serviceability, involving deflection and crack development and propagation, is lacking. This study considers the difference in strength between on-site cast and precast segmental concrete to accurately evaluate the deflection of precast concrete flexural members with joints within the lapped splice. In addition, to reflect an initial crack, the deflection is calculated and evaluated by reflecting the effect of tension-stiffening and subsequently redefining the attached transmission lengths of the left and right sides of the cracked surface as a new cracked region. As a result of explicitly including joint behavior which is considered attached transmission length and characteristic by concrete strength, a more accurate calculation of deflection is developed.

The effects of prestressing methods and prestress levels on the friction losses of prestressed tendons were evaluated in this study. Two full-scale prestressed concrete girders were fabricated and used for the friction loss experiment. The prestress level was varied from 13% to 45% of the ultimate tensile strength of the prestressing tendon, and prestressing was performed by jacking one or both ends. The test results indicated that the actual friction loss measured at low prestress levels was up to 4.3 times higher than the theoretical friction loss. As the prestress level increased, the difference between the measured and theoretical friction losses gradually decreased, and the two eventually converged. On average, the ratio of the prestress force at the jacking end to the prestress force measured at midspan was 85.4% with jacking at both ends, and 81.1% with jacking at one end.