Integrated Design/Construction/Operations Analysis for Fast-Track Urban Freeway Reconstruction

The California Department of Transportation is rehabilitating or reconstructing deteriorated urban freeways using long-life (30+ years) strategies. These pavements were constructed between 1955 and 1970 with design lives of 20 years. This paper summarizes preconstruction analysis of the fast-track pavement reconstruction on Interstate-15 (I-15) at Devore which used two one-roadbed continuous (about 210 h) closures with round-the-clock (24/7) operations. The integrated analysis concluded that the one-roadbed continuous closures are the most economical scenario when compared to traditional nighttime or weekend closures from the perspective of schedule, delay, and costs. The preconstruction was validated with as-built construction and traffic performances monitored during construction. The construction management plan—including contingency, incentives, and critical path method schedule—was developed utilizing the Construction Analysis for Pavement Rehabilitation Strategies (CA4PRS) computer model. The results of this planning study are useful for transportation agencies in developing highway rehabilitation strategies that balance the maximization of construction productivity with a minimization of traffic delay.     

Developing a Traffic Closure Integrated Linear Schedule for Highway Rehabilitation Projects

In recent years, the state departments of transportation have implemented a number of highway rehabilitation projects across the country. These projects differ fundamentally from new highway projects in that they require an uninterrupted flow of traffic throughout both the duration and geometric length of the project. Synchronization of traffic closure with the construction activities is crucial in such projects to avoid the traffic conflicts and prevent idle time for equipment and labor. Although most highway rehabilitation projects involve predominantly linear activities, the techniques of linear scheduling are not readily applicable to highway rehabilitation projects due to the conflict between the workzone and traffic flow. This paper documents the development of a traffic closure integrated linear schedule (TCILS) that addresses both traffic closure and work progress issues. The TCILS generates a single schedule for both the construction activities and the associated traffic closures. Visual and graphical features are also applied in the system, which makes it particularly applicable for highway rehabilitation projects. An actual concrete pavement rehabilitation project using the TCILS is presented as a sample of application. The findings from the sample project, although they are limited, show that the TCILS can be applied to an actual project. With recommended future development, the system is believed to be beneficial for both construction practitioners and academics.     

CONLIGHT: Lighting Design Model for Nighttime Highway Construction

The utilization of nighttime work in highway construction and rehabilitation projects has been increasing in recent years throughout the United States. In this type of projects, construction planners are required to develop and submit a lighting plan that provides: (1) adequate illuminance levels for all planned nighttime construction tasks; (2) reasonable uniformity of light distribution in the work area, and (3) acceptable glare levels to both road users and construction workers. In order to support construction planners in this vital and challenging task, this paper presents a lighting design model, named CONLIGHT, which is capable of considering the specific requirements of nighttime highway construction operations. The model is developed to enable construction planners to evaluate the performance of various lighting plans and select a practical design that complies with all lighting requirements for the nighttime work being planned. An application example is analyzed to illustrate the use of the model and demonstrate its accuracy and capabilities in generating practical lighting plans for nighttime construction and rehabilitation projects.     

Case Study of Urban Concrete Pavement Reconstruction on Interstate 10

Many urban concrete pavements in California need to be reconstructed, as they have exceeded their design lives and require frequent maintenance and repair. Information is needed to determine which methodologies for pavement design, materials selection, traffic management, and reconstruction strategies are most suitable to achieve the objectives of California Department of Transportation’s (Caltrans) long-life pavement rehabilitation strategies (LLPRS) program. To develop construction productivity information for several construction windows, a case study was performed on a Caltrans concrete rehabilitation demonstration project near Los Angeles on Interstate-10, where 20 lane-km was successfully rebuilt using fast setting hydraulic cement concrete (FSHCC) with one weekend closure for 2.8 lane-km and repeated 7- and 10-h nighttime closures for the remaining distance. The concrete delivery and discharge controlled the overall progress. In terms of the number of slabs replaced per hour, the 55-h weekend closure was 54% faster than the average nighttime closure. An excellent traffic management strategy helped to reduce the volume of traffic during the weekend closure and minimize the traffic delay through the construction zone.     

Forensic Investigation of Ultrathin Whitetopping Pavements in Florida

Developed in the early 1990s, ultrathin whitetopping (UTW) is a relatively new technique for asphalt pavement rehabilitation. To evaluate the applicability of UTW pavement in Florida, in 1997, the Florida Department of Transportation (FDOT) constructed an experimental UTW pavement in a weigh station along I-10, located in north Florida. The performance of these test sections, however, was less than ideal, with the observation of some early cracking on the concrete surface, which developed into severe cracking with time. Therefore, a forensic investigation was conducted to determine the causes of the problems in these UTW sections, so that lessons could be learned from this experimental project, the use of UTW under Florida’s conditions could be adequately assessed, and UTW technology could be properly applied in the future. The scope of work consisted of field evaluation, laboratory testing, and pavement design evaluation. Field evaluation included a pavement condition survey, pavement temperature measurement, nondestructive load testing using a falling weight deflectometer, and slab thickness determination. Laboratory tests were performed to determine concrete and asphalt material properties. Other design and traffic data were also acquired from FDOT. Data collected from the field evaluation and laboratory testing were used in conjunction with a mechanistic UTW pavement design/evaluation procedure to determine the possible causes for premature failure. From this comprehensive evaluation, the primary cause for the failure was found to be inadequate UTW pavement design. The inadequacy of the combination of thickness and slab dimensions contributed to the early cracking of the UTW pavement.     

Truck Loading and Fatigue Damage Analysis for Girder Bridges Based on Weigh-in-Motion Data

Based on data collected by weigh-in-motion (WIM) measurements, truck traffic is synthesized by type and loading condition. Three-dimensional nonlinear models for the trucks with significant counts are developed from the measured data. Six simply supported multigirder steel bridges with spans ranging from 10.67 m (35 ft) to 42.67 m (140 ft) are analyzed using the proposed method. Road surface roughness is generated as transversely correlated random processes using the autoregressive and moving average model. The dynamic impact factor is taken as the average of 20 simulations of good road roughness. Live-load spectra are obtained by combining static responses with the calculated impact factors. A case study of the normal traffic from a specific site on the interstate highway I-75 is illustrated. Static loading of the heaviest in each truck type is compared with that of the American Association of State Highway and Transportation Officials standard design truck HS20-44. Several important trucks causing fatigue damage are found.     

Optimum Planning of Highway Construction under A + B Bidding Method

In recent years, many departments of transportation in the United States have started to apply the A + B bidding method in highway projects in order to reduce construction time and minimize its associated traffic congestion and adverse impact on local economies. The application of this method places an increased pressure on contractors to minimize both the time and cost of highway construction. This paper presents a practical model for optimizing resource utilization in highway projects that utilize the A + B bidding method. The model is designed to minimize the total combined bid by identifying the optimum crew formation and the optimum level of crew work continuity for each activity in the project. The model is developed using a dynamic programming formulation and is incorporated in a Windows application that provides a user-friendly interface to facilitate the optimization analysis. An application example of a highway project is analyzed to illustrate the use of the model and to demonstrate its capabilities.     

Time of Sampling Strategies for Asphalt Pavement Quality Assurance

The cost of quality assurance programs in asphalt road construction is high in part because of the need for daily testing. This paper demonstrates the methodology used to investigate the timing of sampling and its effect on the quality assurance program. Fourteen lots over two highway paving projects were tested twice: during construction on a daily basis, and after construction was complete. Three quality measures were compared, namely asphalt content, degree of compaction, and aggregate gradation. The test data during construction were obtained from two sources: the consultant’s quality assurance, and the contractor’s quality control. One-way ANOVA tests and T-tests were used to compare the means. In addition, the arithmetic difference between the means was reviewed to understand how the time of sampling might affect contractor payment adjustments.     

Optimal Lighting Arrangements for Nighttime Highway Construction Projects

This paper presents a decision support system for optimizing temporary lighting arrangements in nighttime highway construction projects. The system is developed as a multiobjective genetic algorithm that is capable of: (1) maximizing average illuminance on construction sites; (2) maximizing lighting uniformity in the work zone; (3) minimizing glare to workers and road users; and (4) minimizing lighting costs. The system is designed to support decision makers in their search for practical lighting arrangements that provide various tradeoffs among these four conflicting objectives. Five decision variables are optimized in the present system, namely: number of lighting equipment, equipment positioning, mounting height, aiming angle, and rotation angle. The system is also designed to consider and satisfy all practical constraints that can be encountered in this lighting design problem. An application example is analyzed to illustrate the use of the system and demonstrate its capabilities in generating near optimal and practical lighting arrangements for nighttime highway construction projects.     

Probabilistic Characterization of Live Load Using Visual Counts and In-Service Strain Monitoring

It has been argued that the AASHTO LRFD design code for maximum live loads on highway bridges is overly conservative. In an attempt to determine the level of conservativeness, if any, the writers developed a methodology incorporating real-time visual data collection from traffic cameras coupled with structural strain response of girder bridges. Average daily truck traffic along with frequency of multiple presences (same lane as well as adjacent lanes) and lane-wise truck traffic distribution were estimated for a steel-girder highway bridge on I-95 in Delaware. These data compared well with predictions from a Poisson process based model developed for this study. Statistical properties of girder moments in single and multiple presence conditions were determined as well. In this particular example, the girder design moment on the 24.6?foot approach span according to AASHTO specifications was found to be about 3.5 times higher than that estimated from the in-service data.     

Stochastic Modeling for Pavement Warranty Cost Estimation

This paper presents a cost estimation model for long-term pavement warranties with multiple distress indicators. One application area for such warranties involves performance-based specifications (PBSs). In contrast to traditional approaches, PBS gives contractors the flexibility to select construction methods, materials, and even design. However, the contractors then must warrant the performance of their work for a specified period of time. Therefore, an accurate estimation of the risks associated with the warranty is a significant cost issue for any contractor to cover potential risks while still being competitive in bidding. Quantitative evaluation of the cost of risk incurred by the warranty has several difficulties. The deterioration of a highway project is a complex process, which is affected by pavement structure, material, traffic load, and weather conditions. Based on a probabilistic risk analysis of failures of performance indicators, the resulting model can estimate the warranty cost at a detailed level. The application of the model has been demonstrated via a numerical case study using long-term pavement performance data.     

Productivity Aspects of Urban Freeway Rehabilitation with Accelerated Construction

Over the last 5?years the California Department of Transportation (Caltrans) has completed three experimental long-life urban freeway rehabilitation projects by utilizing a fast-track (accelerated) construction approach of around-the-clock operations under extended closure. This paper presents the fast-track rehabilitation approaches and the as-built production rates of major rehabilitation operations monitored at the three experimental projects. The monitoring results show that the contractor’s production rates varied considerably depending upon the construction logistics, material delivery and hauling methods, lane-closure tactics, and/or pavement designs being implemented. A higher production rate and a noticeable “learning-curve effect” were observed when full-width rehabilitation was compared with partial-width rehabilitation, when continuous lane reconstruction was compared with random slab replacements, and when full roadbed closures were compared with partial lane closures. Findings in this study suggest that Caltrans should evaluate project-specific conditions and constraints, which might restrict use of a preferred rehabilitation scheme, by taking production rate variances into account when establishing schedule baselines of construction staging plans and incentive/disincentive contracts for urban freeway rehabilitation projects.     

Use of the Long-Term Pavement Performance Database in the Pavement Engineering Curriculum

In this paper the writers demonstrate the inclusion of the Long-Term Pavement Performance (LTPP-DATAPAVE 3.0) data within the pavement engineering curriculum at Michigan State University (MSU). The paper presents two examples, one from an undergraduate course on pavement rehabilitation and one from a graduate course on pavement analysis and design. These examples illustrate the use of LTPP data in computing responses, predicting traffic, developing rehabilitation strategies, and predicting performance of both rigid and flexible pavements.     

Probabilistic Approaches for Pavement Fatigue Cracking Prediction based on Cumulative Damage Using Miner’s Law

In mechanistic-empirical (M-E) pavement design, pavement damage is modeled as a random variable with a pre-specified distribution (normal or lognormal). The extent of fatigue cracking in terms of percentage cracking is computed as the probability of cumulative damage exceeding unity. This paper provides a methodological framework for characterizing damage distribution under mixed traffic loading (multiple strain levels) with an improved forecast of traffic spectrum based on renewal theory. Using the linear Miner’s law for damage accumulation, analytical representation of damage distribution is obtainable owing to the proportional relationship between maximum tensile strain of pavement and traffic load under linear elasticity condition. Numerical computation shows that percent of cracking from derived damage distribution is greater than that from hypothetical normal or lognormal distributions traditionally used in the M-E pavement design. The method developed here and the derived model can be used in pavement design and pavement management systems.     

Long‐Range Forecasting Highway Construction Costs

In the process of decision making for design and execution of highway construction projects, long‐range cost forecasting is one of the most significant and complicated problems. This paper describes the development of a model that enables the user to make long‐range cost projections, taking into consideration general characteristics of the highway construction industry, as well as pertinent local conditions. The model presented uses conventional statistical methods to represent the main categories of typical jobs in the highway construction industry. From these categories, a composite model is created by assigning different weights to the input elements costs and then choosing a series of indicators to predict price trends for each separate element of the composite model. Use of this model reveals that bid volume in a certain area is a factor that has significant influence upon cost forecasts. This paper is accompanied by a case study based on actual data from highway construction projects performed for the Florida Department of Transportation in the years 1968–1981.     

Modeling Permanent Deformation of Unbound Granular Materials under Repeated Loads

Finite-element analysis on a pavement structure under traffic loads has been a viable option for researchers and designers in highway pavement design and analysis. Most of the constitutive drivers used were nonlinear elastic models defined by empirical resilient modulus equations. Few isotropic/kinematic hardening elastoplastic models were used but applying thousands of repeated load cycles became computationally expensive. In this paper, a cyclic plasticity model based on fuzzy plasticity theory is presented to model the long-term behavior of unbound granular materials under repeated loads. The discussion focuses on the model parameters that control long-term behavior such as elastic shakedown. The performance of the constitutive model is presented by comparing modeled and measured permanent strain at various numbers of load cycles. Calculated resilient modulus from the complete stress-strain curve is also discussed.     

Long-Term Field Performance of Cold In-Place Recycled Roads in Iowa

Cold in-place recycling (CIR) is one of the most effective methods to rehabilitate asphalt pavements. In fact, most CIR roads have performed well at low cost in Iowa since the first CIR road was constructed in 1986. However, some CIR roads have reached failures earlier than their expected design lives because there is no design standard for designing CIR roads with a limited amount of past performance information. Some of the most prominent problems seemed to have come from selecting CIR in areas where there are poor subgrades. Therefore, it is critical to collect CIR performance data along with falling weight deflectometer (FWD) data in order to develop performance models. The main purpose of this paper is to document that effort. The performance models were developed on the basis of historical data collected from CIR roads in Iowa. First, an inventory of CIR roads was created which includes construction information, subgrade and base characteristics, and traffic levels. In consideration of pavement age, level of traffic, and subgrade condition, 26 test sections were selected from the inventory of CIR roads and pavement surface distress surveys were conducted on these roads using an automated image collection system. Distress data were then compiled to compute pavement condition index (PCI) for each test section. FWD data were collected from each test section to determine its relative soil support condition. Finally, to determine their long-term performance, the PCI values were plotted against the pavement age for each group of pavements categorized by their soil support conditions and traffic levels. Overall, it can be concluded that the CIR roads in Iowa, all under traffic level of annual average daily traffic of 2,000, have performed very well and predicted to last up to 25 years before reaching the poor condition (PCI = 40) when the pavements are to be rehabilitated. The CIR roads with a good subgrade support, however, are predicted to last up to 35 years.     

从韶钢大道的改造谈路面病害的修复方法

介绍了韶钢大道工农路段病害的原因、改造方案、改造效果，所采用的方法和内容可供公路工程建设或改造时参考．     

Automated GIS-Based System for Speed Estimation and Highway Safety Evaluation

Although geographic information systems (GISs) have been applied in different areas of transportation, full use of their potential in speed profile analysis and highway design consistency studies has yet to be made. The possibilities that GISs offer for analysis and the increasing number of highway inventories supported by such systems, including traffic data and crash rates, suggest that the implementation of a highway design consistency analysis module within a GIS will facilitate and improve road safety studies. It is with this aim that a GIS-based computer system that builds vehicle speed profiles and analyzes highway design consistency has been developed, in which an operating speed prediction model, acceleration/deceleration rates, and other features can be configured by the engineering user in order to obtain an analysis that is more representative of drivers and local conditions. Application of this system to the study of the design consistency of highways is described, using three examples.