Introduction to Infrastructure: An Introduction to Civil and Environmental Engineering First Edition Michael R. Penn and Philip J. Parker Chapter 3 Structural Infrastructure Copyright © 2012 by John Wiley & Sons, Inc. All rights reserved. Infrastructure Sectors: • Transportation, Environmental, and Structural Subsectors: • Mass transit, aviation, etc. Components: • Roadways, rail lines, etc. Subcomponents: • Curbs, pavement, etc. ASCE Report Card started 1988 by congressional chartered commission. • • • • • 1988: C 1998: D 2001: D+ 2005: D 2009: D Schools are typically one of the largest expenses for a community. Each community must decide how large of a school to build. • Too big: huge debt. • Too small: substandard temporary classrooms. Difficult in many areas with rapidly growing or shrinking populations. There have been no extensive studies since 1999. Significant budget cuts in the last several years. Huge disparity in education quality linked to district affluence. Choice of bridge type depends on: • • • • • Distance to be crossed Site geology Construction conditions Traffic type Funding • • • • • • ASCE 2009 Grade: C 600,905 bridges Average age: 43 years old Typical design age: 50 years 12.1% are structurally deficient 14.8% are functionally obsolete US bridge stats: Used for navigation, flood control, hydroelectric power, water supply, flood control, and recreation. Almost exclusively earthen or concrete. Major dams – over 50ft tall with >5,000 ac-ft of storage or anything with >25,000 of ac-ft storage. Spillways – engineered channels to keep dams from overtopping by bypass the dam. Fish ladders/elevators – mechanisms that allow fish migration over the dam. Over 80,000 damn in the US 1,700 high-hazard dams in need of repair (2007) Levees/Dikes – earthen embankments Floodwalls – typically concrete • Floodgates – Installed in floodwalls to be closed during flood conditions. ASCE 2009 Grade: D- Only 10 states keep listings of levees. Only 23 states have agencies in charge of levee safety. Levees in 22% of all counties in the US. Levees that once just protected agriculture now protect residential neighborhoods. Retaining wall – used to eliminate slopes to create a greater developable area. Must be able to resist lateral earth pressure and hydrostatic pressure (unless properly drained.) According to ASCE we need an additional investment of $641 billion !