Waste Water Force Main Pipe Construction Alternatives to Protect Existing Foundations in the City of Chandler: Case Study

To provide additional wastewater capacity and redundancy in South Chandler, Arizona, a new 28” High Density Polyethylene (HDPE) force main was installed from the upsized Kyrene Lift Station three miles east to tie into an existing 66” transmission sewer line. The force main was installed under the State Route Loop 202 (SR 202L) freeway through existing 48” steel casings constructed ten years prior. Additionally, the force main was constructed through a narrow Arizona Department of Transportation (ADOT) corridor, which required clearance from existing utilities, including overhead 69 kV power poles. Two locations required innovative solutions to both access the existing sleeves and cross the transmission power pole foundations: 1) crossing of the 69 kV power pole required detailed slope stability analysis and location specific trench backfilling; and 2) access to the existing 48” was within 15 feet of an existing ADOT sound wall. Various alternatives for access were analyzed in this paper including temporary shoring, sheet pile installation, and full wall replacement and reconstructing on drilled shafts. Based on the objectives above, the existing power pole does not have sufficient embedment for maximum design loads but is stable with reduced load factors and lower operation wind forces. Also, for construction issue with the existing ADOT sound wall, the temporary shoring and sheet piles used due to the geotechnical conditions and construction costs

The investigation of methods to assist decision-makers regarding bridge maintenance, rehabilitation, and restoration activities

The ability to predict the deterioration pattern of bridges can assist decision makers in determining when and whether to ignore, refurbish/rehabilitate, or replace a bridge. This dissertation formulates and applies two models, one deterministic and the other probabilistic, capable of predicting future condition ratings of the three main components of a bridge; wearing surface, superstructure, and substructure. The contribution to bridge deterioration by environment factors including freeze-thaw cycles, de-icing salts, and vehicular traffic, are also examined through analysis and comparison of deterioration of selected bridges from two contrasting regions in the Province of Ontario.A deterministic approach to formulating a failure prediction model incorporates a Family of Curves. This approach utilizes a least squares model to fit non-linear polynomial curves to historical bridge inspection data. A probabilistic approach to formulating a failure prediction model incorporates a Markovian Process which provides information on the probability of moving from one condition state (or rating) to another given the present condition state. Both of these models generate curves depicting deterioration patterns for the three main components of a bridge.Perhaps the most notable contribution of this work is the development of a method for generating failure prediction curves based on age of "original & renewed component." This approach excludes the effects of major repairs and provides the most realistic representation of bridge component deterioration. Success in testing the predictive ability of this approach on sampled bridges demonstrates the value to decision makers of the model developed in this research.U of I OnlyETDs are only available to UIUC Users without author permissio

Cost Analysis of Green Infrastructure Compared to Conventional Stormwater Storage

Low Impact Development (LID), or green infrastructure, refers to a land planning and engineering design practice to address urban storm runoff. The nature of LID is to mimic the pre-development environment to retain runoff through infiltration, retention, and evaporation. Despite the fact that numerous studies have analyzed the performance of runoff volume reduction and peak flow of various green infrastructures, little is known regarding the economic benefits of adopting LID practices. In this research, three completed construction projects in the Phoenix, Arizona metropolitan area were selected to perform an alternative LID design including extensive green roof (GR) and permeable interlocking concrete pavement (PICP), to determine the cost effectiveness of using LID to reduce the use of a conventional stormwater storage system. A life cycle cost (LCC) analysis was conducted to better understand the cost benefits of applying LID to meet current drainage design criteria as per the project requirements. The results found that applying LID resulted in an average LCC saving rate of 23% compared to a conventional stormwater storage system over a 50 year service life and 15.1% over a full LID (GR+PICP) strategy.  Furthermore, it was discovered that LID has little cost savings benefits when constructing above-ground retention basins due to cheaper associated construction costs.</jats:p