Introduction and Overview External Loads Design of Gravity Flow Pipes Design of Pressure Pipes Buried Pipe Products

Buried Pipe Design

Probability-based codified design: past accomplishments and future challenges

Shear Tests of High- and Low-Strength Concrete Beams Without Stirrups

Prestressed concrete cylinder pipe (PCCP) tends to be of large diameter, making many failures of this type of pipe relatively catastrophic and costly. To date, most research has been focused on PCCP inspection technologies and performance prediction in order to minimize the risk to utilities from failures. The performance of Prestressed Concrete Cylinder Pipe has been an item of interest to water utilities for a long time. Fifteen years ago, AWWA Research Foundation (AwwaRF) and the Bureau of Reclamation initiated a study, Performance of Prestressed Concrete Pipe that was unfortunately never published. AwwaRF has also funded studies to develop software that uses fuzzy logic (Kleiner, et al. 2005) to predict future PCCP behavior useful if a utility has sufficient data from actual field experience with PCCP. Another AwwaRF report (Romer, et al. 2005), developed methodologies, techniques, protocols, and technology for identifying the specific conditions that lead to corrosion failures of PCCP. That study included testing the effects of cathodic protection on pre-existing notches in PCCP reinforcing wires, and compared the accuracy of similar internal investigative tools for the detection of broken PCCP reinforcing wires. This paper presents preliminary results of the most recent AwwaRF funded study, intended to collect, codify, expand upon, and disseminate the results of the previous studies on PCCP failures. The project began with a survey of a selected group of water utilities with a fair amount of PCCP in their systems, selected carefully to represent the range of conditions and variables that affect PCCP performance across North America. The survey results, combined with a pre-existing database of over 450 PCCP failures, were statistically projected over the installed PCCP base of North America, and provide a surprising indicator of failures and failure rate of PCCP.

Failure of Prestressed Concrete Cylinder Pipe

Constrained funding requires that resources be allocated and used efficiently in order to maximize the safety, utility, and state of good repair of public facilities. During the life cycle of any public facility various risk factors might influence the performance and operating cost of the infrastructure. The risk factors influence the longevity, fitness, and adaptability of the facility dictating the necessity and timing of renewal or rehabilitation. This paper identifies risk factors that influence the cost-effective management, operation, and maintenance of bridges, roads and highways, and subway stations as well as how and when in the project life cycle the identified risk factors impact the associated facility costs.

Risk Factors Affecting Management and Maintenance Cost of Urban Infrastructure

The paper presents a description of a new computerized direct design method for buried concrete pipe named SPIDA (Soil-Pipe Interaction Design and Analysis). Also the technical basis and some of the results of SPIDA analyses and designs obtained to date with this method are summarized. The soil-structure interaction finite element system, the salient characteristics of the soil and pipe models, the soil and pipe properties and the principal features of the soil meshes that were established for embankment and trench installations are described in the paper. Also summarized are the new reinforced concrete design methods that were developed for shear, radial tension, crack control, and cracked section stiffness. SPIDA calculated deflections for four buried concrete pipe test installations are presented and compared to the measured deflections.

SPIDA: An Analysis and Design System for Buried Concrete Pipe

A new design procedure is presented for prestressed concrete cylinder pipe subjected to internal pressure, external loads, and pipe and fluid weights based on certain limit‐states design criteria. The proposed design criteria consist of: (1) Serviceability limits for crack control in the core and the coating of the pipe; (2) elastic limits to maintain repeatability; and (3) strength limits. Design criteria for calculating combined loads and pressures corresponding to these limit states are described with the reasoning that led to their recommendation. The results of a series of carefully conducted combined‐load tests on three embedded‐ and three lined‐cylinder pipes are presented and compared to the combined loads calculated based on the proposed limit‐states design criteria. The test results show the accuracy of the proposed criteria and procedures for predicting the combined loads at first visible core and coating cracks. The actual design procedures that are used with these limit state criteria are pre...

Limit-states design of prestressed concrete pipe i: criteria

Factors of safety for flexural members designed using the ASCE 7‐88 and American Institute of Steel Construction (AISC) LRFD 1986 standards are investigated and found to represent a significant reduction in reliability compared to previous AISC allowable stress methods for typical flexural members. This contradicts statements in the commentary of AISC LRFD 1986, which states that the reliability index for typical members has not been reduced. Also, experience from structural failure investigations and peer reviews shows that actual dead‐load variations are not consistent with the 1.2 dead‐load factor used in these standards. Further development of consistent load and resistance factors by a joint committee of practicing structural engineers under auspices of ASCE, AISC, American Concrete Institute (ACI), and American Institute of Timber Construction (AITC) is recommended. Suggestions are also made for interim load and resistance factors that maintain the reliability level inherent in current working stres...

Public safety - is it compromised by new lrfd design standards?

Tests conducted by the prestressed concrete pressure pipe industry in the United States during the past four decades have been gathered and analyzed. The present industry design procedures are summarized. Test results are compared with design limits defined by AWWA C301 and these industry design procedures. The results show that the resultant prestress calculated by the present industry procedures correlates well with test results. Ratios of test loads that produce the first visible cracks, 0.005–0.010‐in. (0.13–0.25‐mm) wide cracks, the ultimate strength in three‐edge bearing load, and the burst strength of prestressed concrete pipe to the design limit loads are presented. The test results depict the ability of prestressed concrete pipe to control and limit crack width.

Frank J. Heger

Papers

SPIDA: An Analysis and Design System for Buried Concrete Pipe

Limit-states design of prestressed concrete pipe i: criteria

Public safety - is it compromised by new lrfd design standards?

Experimental evaluation of design methods for prestressed concrete pipe

Buckling of Thin Concrete Domes