Bridge Construction Site Research Articles

Managing construction schedule by telepresence: Integration of site video feed with an active nD CAD simulation

Abstract In recent years, the increased utilization of building information modeling (BIM) has brought attention to the need for BIM-based operation systems that provide a decision-making feature in addition to visual information. This study constructed a project schedule management system that integrates the data points of an nD computer-aided design (CAD) object (e.g., schedule and resource information) with a telepresence concept video management operation system. A methodology was developed that allows the user to monitor the current construction status relative to the design and verify the completion of the facility through real-time comparison between the planned process represented by the nD object and the actual image of the construction site sent from an on-site webcam. An active nD CAD system was developed that possesses features such as a comparative simulation between the on-site image and a 4D object to minimize interference between processes and a 5D object that is specialized to the resource mobilization level of the field. A telepresence-based nD CAD system was developed based on this methodology, and the practicality of the system was verified by webcams installed on a bridge construction site. Thus, the project manager is not only able to utilize the nD object for visualization but is also able to use the system as a decision-making system to formulate the most appropriate project schedule by comparing the nD object with the actual on-site image.

Durability of latex-modified concrete carried by ready-mix truck for concrete rooftops

This study was initiated to investigate the properties of latex-modified concrete (LMC) carried by ready-mix trucks. Generally, LMC used as an overlay in bridge projects is hardened much more quickly than normal concrete, and the LMC is fabricated by adding latex into the concrete mixture in a mobile mixer near the bridge construction site. LMC is particularly used due to its exceptional bond strength and durability. This study focused on the use of LMC for the overlay of a building rooftop, such as might be required when the concrete on a concrete rooftop exposed to severe weather in winter is beyond repair and thus needs to be replaced. However, for building repairs in a city, a mobile mixer may be unsuitable for use due to the associated loud noise and the restricted available area. In such a case, the LMC would need to be fabricated in a cement plant and then transported to site in ready-mix trucks. In this study, several experiments were conducted to verify whether transported LMC can work effectively and maintain durability. Slump test results revealed a little slump loss after LMC was carried for 60 min. The overall experimental results showed that LMC transported in ready-mix trucks could be an appropriate alternative method to repair deteriorated concrete on building rooftops in urban areas.

Selection of a Bridge Construction Site Using Fuzzy Analytical Hierarchy Process in Geographic Information System

Selection of bridge construction sites over rivers is one of the most important tasks in construction feasibility studies. In this paper, potential sites for the construction of a river bridge are ranked for suitability using analytical hierarchy process for a river in the northern part of Iran. Fuzzy logic is used to incorporate the uncertainty associated with decision making into the model. Geographic information system is used to facilitate the decision-making process by determining alternative sites and evaluating the selection criteria. A floodplain is determined by the river reach using a hydraulic simulation. This is done to identify the length and height of potential bridges for each site. Two scenarios are analyzed in this paper: the first ranks bridge construction sites regardless of the location of an existing bridge and the second ranks bridge construction sites considering the existing bridge. The result of this analysis shows that the existing bridge is one of the best locations but not the best one.

A hybrid model for selecting location of mobile cranes in bridge construction projects

Mobile cranes are considered one of main equipment in bridge construction projects. Choosing the best locations for mobile cranes in bridge construction sites is an important task that must be done efficiently. This paper presents a hybrid model that integrates Genetic Algorithms and Bridge Information Modeling to choose the best locations of mobile cranes in bridges construction sites, taking into account different constraints related to: safety, clearance, existing site conditions, construction schedule, and duration of erecting structural members. The proposed model is novel since it explores more features of Bridge Information Modeling such as decision making including location of mobile cranes and less boom maneuvers.

DEVELOPING A MODEL TO ENHANCE LABOR PRODUCTIVITY USING BRIDGE CONSTRUCTION BENCHMARK DATA

The Labor Working Status Monitoring (LWSM) Model that incorporates the WRITE and the industry benchmark data was developed through the five steps to enhance labor producitivty in bridge construction operations. The first step of the development process was to conduct a literature review, followed by the second step which was to develop the WRITE. During the development, the authors identified the necessary hardware and software for the WRITE and outlined a schematic to show the connection of major hardware components. The third step was to develop the LWSM Model for monitoring the on-site construction labor working status by comparing data from the WRITE with the industry benchmark data. A survey methodology was used to acquire industry benchmark data from bridge construction experts. The fourth step was to demonstrate the implementation of the LWSM Model at a bridge construction site. During this phase, labor working status data collected using the WRITE was compared with the benchmark data to form the basis for the project managers and engineers to make efficiency improvement decisions. Finally, research findings and recommendations for future research were outlined. The success of this research made several contributions to the advancement of bridge construction. First, it advances the application of wireless technology in construction management. Second, it provides an advanced technology for project managers and engineers to share labor working status information among project participants. Finally, using the developed technology, project managers and engineers can quickly identify labor efficiency problems and take action to address these problems. . Key words: bridge, benchmark, construction, management, monitoring, productivity, wireless.

단면 상세가 변화된 LB-DECK의 균열하중에 대한 실험적 연구

LB-DECK, a precast concrete panel type, is a permanent concrete deck form used as a formwork for cast-in-place concrete pouring at bridge construction site. LB-DECK consists of 60 mm thick concrete slab and 125 mm height Lattice-girders partly embedded in the concrete slab. These decks have been applied to the bridges, which girder spacings are short enough to resist longitudinal cracking caused by construction loads. This paper presents experimental research work conducted to evaluate the cracking load of LB-DECKs designed for long span bridge decks. Twenty four non-composite beams and four composite beams are fabricated considering three design variables of thickness of concrete slab, height of lattice-girder, and diameter of top-bar. Static loads controlled by displacements are applied to test beams to obtain cracking and ultimate loads. Vertical displacements at the center of beams, strains of top-bar, crack propagation in concrete slab, and final failure modes are carefully monitored. The obtained cracking loads are compared to the analytical results obtained by elastic analyses. Long-term analyses using age-adjusted effective modulus method (AEMM) are also conducted to investigate the effects of concrete shrinkage on the cracking loads. Based on the test results, the tensile strength and the design details of LB-DECKs are discussed to prevent longitudinal cracking of long span bridge decks.

RFID and CCTV-Based Material Delivery Monitoring for Cable-Stayed Bridge Construction

The effective management of construction materials is critical to the successful execution of large-scale infrastructure projects. A cable-stayed bridge construction, for which diverse and complex structural components must be monitored, is no exception. To improve the effectiveness and efficiency of bridge-component management, we developed a material delivery monitoring system using closed-circuit television (CCTV) and radio frequency identification (RFID) technologies. The RFID technology was used to identify the structural components of the cable-stayed bridge; CCTV cameras acquired site image data that helped field engineers confirm the delivery of construction components. The RFID information and image data were saved to a main server database for systematic management of construction materials. A case study conducted at a cable-stayed bridge construction site verified the applicability and capability of the developed system. The system has considerable potential to significantly improve the current...

Evaluation of Cone Penetration Test-Based Settlement Prediction Methods for Shallow Foundations on Cohesionless Soils at Highway Bridge Construction Sites

The cone penetration test (CPT) method is gaining popularity in the United States as one of the premier subsurface exploration techniques. The writers previously monitored settlement behavior of spread footing foundations at five highway bridge construction sites in Ohio and evaluated the standard penetration test-based settlement prediction methods in light of the field performance data. The authors recently conducted CPT sounding at these bridge sites. In this paper, settlement behavior of five spread footings resting on cohesionless soils at two sites were predicted with the CPT-based settlement prediction methods proposed by Amar, DeBeer, Meyerhof, and Schmertmann. The results showed that the prediction methods by Schmertmann and DeBeer were both conservative but reasonably reliable in predicting the settlement of shallow foundations observed in the field.

Axial and Lateral Load Performance of Two Composite Piles and One Prestressed Concrete Pile

Composite piles use fiber-reinforced polymers (FRPs), plastics, and other materials to replace or protect steel or concrete, with the intent being to produce piles that have lower maintenance costs and longer service lives than those of conventional piles, especially in marine applications and other corrosive environments. Well-documented field loading tests of composite piles are scarce, and this lack of a reliable database may be one reason that composite piles are not in widespread use for load-bearing applications. The purpose of this research is to compare the axial and lateral load behavior of two different types of composite test piles and a conventional prestressed concrete test pile at a bridge construction site in Hampton, Virginia. One of the composite piles is an FRP shell filled with concrete and reinforced with steel bars. The other composite pile consists of a polyethylene plastic matrix surrounding a steel reinforcing cage. The axial structural stiffnesses of the prestressed concrete pile and the FRP pile are similar, and they are both much stiffer than the plastic pile. The flexurel stiffness of the prestressed concrete pile is greater than that of the FRP pile, which is greater than the flexural stiffness of the plastic pile. The axial geotechnical capacities of the test piles decreased in order from the prestressed concrete pile to the FRP pile to the plastic pile. The prestressed concrete pile and the FRP pile exhibited a similar response for lateral load versus deflection, and the plastic pile was much less stiff in lateral loading.

Effect of Pumping on Properties of Bridge Concrete

Pumping of concrete is widely used in large highway projects due to convenience and economy of placement. The short-term effects of pumping on the durability of concrete is well documented, whereas the long-term effects on concrete durability is not known. Both types of effects were studied herein through collection and testing of 73 concrete samples from the Florida Department of Transportation bridge construction sites before and after pumping. The tests performed were air content, slump, unit weight, compressive strength, rapid chloride permeability, and water permeability. The air content and the slump of concrete decreased by about 1% and 13 mm (0.5 in.) on average, respectively, due to pumping. The unit weight and compressive strength of concrete were found to increase by about 24 kg/m3 (1.5 pcf) and 1.83 MPa (266 psi), respectively, due to pumping. Although test results are not statistically significant, pumping decreased the water and chloride ion permeabilities in the majority of tested samples. Results show that pumping does not have detrimental effects on concrete properties. In many cases, it results in stronger, denser, and more durable concrete. It is suggested that pumping be continued as a means of concrete placement in Florida Department of Transportation projects with confidence.

Variations in the Short- and Long-Term Characteristics of Bridge Concrete Due to Transportation Techniques

The short-term effects of pumping on concrete are well documented, although the long-term effects on concrete durability are not known. Pumping of concrete is widely used in large highway projects because of its convenience and economy of placement. Both types of effects were studied through collection and testing of 73 concrete samples from the Florida Department of Transportation (FDOT) bridge construction sites before and after pumping. The tests performed were air content, slump, unit weight, compressive strength, rapid chloride permeability, and water permeability. The air content and the slump of concrete decreased by about 1 percent and 13 mm (0.5 in.) on average, respectively, due to pumping. The unit weight and compressive strength of concrete increased by about 24 kg/m3 (1.5 pcf) and 1.83 MPa (266 psi), respectively, due to pumping. Pumping decreased the water and chloride ion permeabilities in the majority of tested samples. Results show that pumping does not have detrimental effects on concrete properties; in fact, in many cases, it results in stronger, denser, and more durable concrete. Results indicate that pumping can be continued with confidence as a means of concrete placement in FDOT projects.

A structurally integrated Bragg grating laser sensing system for a carbon fiber prestressed concrete highway bridge

Carbon fiber based composite material is of considerable interest for the replacement of steel in large concrete structures, such as bridges, where corrosion is a serious problem. A new two-span concrete highway bridge built in the city of Calgary in 1993 is the first in the world to use carbon fiber composite prestressing tendons in several of its precast concrete deck support girders. We have instrumented a number of these girders with an array of fiber optic intracore Bragg grating sensors in order to monitor the changes in the internal strain that take place over an extended period of time. A four-channel fiber laser demodulation system was developed for interrogating the set of Bragg grating sensors embedded within the bridge girders. This demodulation system was demonstrated to be rugged, compact and transportable to the bridge construction site where it allowed changes in the internal strain on all three types of prestressing tendon (steel and two types of carbon fiber composite) to be tracked over several months. The same set of structurally integrated Bragg grating sensors has also been used to measure the change in the internal strain within the deck girders arising from both static and dynamic loading of the bridge with a 21 ton truck. This first permanent testbed for structurally integrated Bragg grating sensors demonstrates the feasibility of building into new bridges fiber optic long-term structural monitoring sensing technology that will allow the use of these advanced composite materials to be monitored in a manner not previously practical. The strain information available from this type of monitoring system will assist engineers in their assessment of new materials and innovative design features, and has a potential role in maintenance and repair activities.