Andrzej S. Nowak

Bio: Andrzej S. Nowak is an academic researcher from Auburn University. The author has contributed to research in topics: Girder & Structural load. The author has an hindex of 36, co-authored 217 publications receiving 5795 citations. Previous affiliations of Andrzej S. Nowak include University of Michigan & Washington State Department of Transportation.

Reliability of Structures

Abstract: This book enables both students and practicing engineers to appreciate how to value and handle reliability as an important dimension of structural design. The book discusses the concepts of limit states and limit state functions, and presents methodologies for calculating reliability indices and calibrating partial safety factors. It also supplies information on the probability distributions and parameters used to characterize both applied loads and member resistances. This book contains more discussions of United States (US) and international codes and the issues underlying their development. There is a significant discussion on Monte Carlo simulation. The books' emphasis is on the practical applications of structural reliability theory rather than the theory itself. Consequently, probability theory is treated as a tool, and enough is given to show the novice reader how to calculate reliability. Some background in structural engineering and structural mechanics is assumed.

Calibration of lrfd bridge design code

Abstract: This report presents the results of a study on the calculation of load and resistance factors for the AASHTO "LRFD Bridge Design Specifications" (1994). Information on various load models, and procedures for determining reliability indices, are included. The contents of this report will be of immediate interest to bridge and structural engineers, bridge researchers, and others interested in the development of the AASHTO LRFD design code and in probabilistic design methods.

Simulation of dynamic load for bridges

Abstract: This paper deals with the analysis of dynamic loads in bridges. Models are developed for trucks, road surface (roughness) and the bridge. The statistical parameters are based on the results of surveys, tests and analysis. Truck parameters include the body (mass), suspensions, and tires. Road profiles are simulated using stochastic processes (power spectral density function). A bridge is treated as a prismatic beam. The Monte Carlo method is used to simulate the traffic on the bridge. Random variables include the truck type, total weight, axle distances, and speed. Calculations are carried out for steel and prestressed concrete girder bridges. The dynamic load factors for a bridge design code are calculated based on the 75 year mean maximum loads. The analysis is performed for single trucks and for two trucks (side by side). Dynamic loads are lower for heavier trucks and also lower for two trucks. The calculated static and dynamic deflections are presented in tables and graphs as a function of gross vehicle weight, and span and axle distance. Simulated deflections indicate that the dynamic component is not correlated with the static component. Therefore, the dynamic loads are lower for heavier trucks.

Guide for the Design and Construction of Externally Bonded FRP Systems for Strengthening Concrete Structures

Abstract: *Co-chairs of the subcommittee that prepared this document. Note: The committee acknowledges the contribution of associate member Paul Kelley. ACI encourages the development and appropriate use of new and emerging technologies through the publication of the Emerging Technology Series. This series presents information and recommendations based on available test data, technical reports, limited experience with field applications, and the opinions of committee members. The presented information and recommendations, and their basis, may be less fully developed and tested than those for more mature technologies. This report identifies areas in which information is believed to be less fully developed, and describes research needs. The professional using this document should understand the limitations of this document and exercise judgment as to the appropriate application of this emerging technology.

A review of structural health monitoring literature 1996-2001

Abstract: Staff members at Los Alamos National Laboratory (LANL) produced a summary of the structural health monitoring literature in 1995. This presentation will summarize the outcome of an updated review covering the years 1996 2001. The updated review follows the LANL statistical pattern recognition paradigm for SHM, which addresses four topics: 1. Operational Evaluation; 2. Data Acquisition and Cleansing; 3. Feature Extraction; and 4. Statistical Modeling for Feature Discrimination. The literature has been reviewed based on how a particular study addresses these four topics. A significant observation from this review is that although there are many more SHM studies being reported, the investigators, in general, have not yet fully embraced the well-developed tools from statistical pattern recognition. As such, the discrimination procedures employed are often lacking the appropriate rigor necessary for this technology to evolve beyond demonstration problems carried out in laboratory setting.

On Engineered Cementitious Composites (ECC)

Abstract: This article surveys the research and development of Engineered Cementitious Composites (ECC) over the last decade since its invention in the early 1990's. The importance of micromechanics in the materials design strategy is emphasized. Observations of unique characteristics of ECC based on a broad range of theoretical and experimental research are examined. The advantageous use of ECC in certain categories of structural, and repair and retrofit applications is reviewed. While reflecting on past advances, future challenges for continued development and deployment of ECC are noted. This article is based on a keynote address given at the International Workshop on Ductile Fiber Reinforced Cementitious Composites (DFRCC) - Applications and Evaluations, sponsored by the Japan Concrete Institute, and held in October 2002 at Takayama, Japan.

Interface tailoring for strain-hardening polyvinyl alcohol-engineered cementitious composite (PVA-ECC)

Abstract: This paper presents the development of the PVA-ECC in the context of material design under the guidance of micromechanical tools. Specifically, this work illustrates how the fiber/matrix interface may be engineered to accommodate the requirements imposed by the micromechanical models, thus highlighting the importance of interface tailoring on the composite performance. This micromechanics-based material design approach is broadly applicable to achieving high-performance composites with low fiber content for cost-effective structural applications.