Motagua Bridge Project

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Motagua Bridge Project

• Design Selection Construction Process
• Presented by James Ritter

Bridge over the Rio Grande Motagua near La
Garrucha, Guatemala
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Motagua Bridge Project

• Design Selection and Construction Process

• Project Background
• Design
• Alternatives
• Selection Methodology
• Construction Process
• Unique Construction Elements
• Construction Overview
• Questions

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Project Background

• Project Description
• Design and construction of a vehicle bridge over
  the Rio Motagua
• Key Project Partners
• PAVA Local Guatemalan Non-Profit
• Marquette University College of Engineering
• Southminster Presbyterian Church Waukesha, WI
• Wisconsin Professional Partners Chapter of
  EWB-USA

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Project Background

• Project Location
• On the Rio Grande Motagua near La Garrucha,
  Guatemala

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Project Background

• Existing Conditions
• Confluence of the Rio Motagua and Rio Cujil
• Exposed bedrock

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Project Background

• Existing Conditions
• The existing bridge construction
• Historical and sentimental value

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Design Alternatives

• Steel Girder Design
• Five wide flange structural steel girders
• Located at existing structure
• Two Span Concrete T-Beam
• Four concrete girders
• Located approximately 100 upstream
• Single-Span Concrete T-Beam
• Five concrete girders
• Located at existing structure or directly
  upstream

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Selection Methodology

• Steel Girder Design (Located at existing
  structure)
• Pros
• Less shoring
• Shorter construction schedule
• Cons
• Extensive demolition of existing structure
• Unknowns of utilizing portions of the existing
  abutments
• Sentimental and historical value
• Beam size
• Cost
• Need for hoisting equipment
• Alternative discarded as impractical cost
  prohibitive

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Selection Methodology

• Concrete T-Beam Alternatives
• Both two span and single span alternatives
  required
• Extensive formwork and shoring towers
• Large volumes of concrete to be poured
• Longer construction schedule
• Relatively equal cost estimates
• Similar construction schedules

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Selection Methodology

• Two Span Concrete T-Beam Design
• (Located approximately 100 upstream of existing
  structure)
• Cons
• Requires construction of a permanent pier in the
  riverbed
• Additional formwork and excavation for pier
• Unknown conditions of riverbed
• Concerns regarding potential for scour
• Possibility of changing hydraulic conditions
• Alternative was eliminated based on concerns
  regarding permanent pier construction.

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Selection Methodology

• Selected Design
• Single-Span Concrete T-Beam
• (Located directly upstream of existing structure)
• Lowest Cost
• No Permanent Pier
• No Demolition
• Preserve Existing Structure
• Hydraulic Conditions Will Remain Unchanged

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Selection Methodology

• Selected Design

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Construction Process

• Unique Construction Elements
• Bedrock Excavation
• Temporary Pier Construction
• Falsework Trusses

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Unique Construction Elements

• Bedrock Excavation

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Unique Construction Elements

• Temporary Pier Construction

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Unique Construction Elements

• Temporary Pier Construction

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Unique Construction Elements

• Falsework Trusses

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Unique Construction Elements

• Falsework Trusses

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Construction Overview

• Advanced Site Preparation
• Bedrock excavation
• Construction of Primary Bridge Structure
• Two groups of volunteers working with the local
  community
• 16 days of construction over a three week time
  period
• Construct footings, abutments, temporary pier
  truss false work structure, beams, and bridge
  deck
• Finishing Construction
• Local mason and local community construct wing
  walls and railings, and remove the false work

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Construction Overview

• Pre-Construction

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Construction Overview

• Pier Island Construction

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Construction Overview

• Footing Construction

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Construction Overview

• Abutment Pier Construction

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Construction Overview

• False Work Construction

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Construction Overview

• Beam Construction

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Construction Overview

• Deck Construction

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Construction Overview

• Deck Construction

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Construction Overview

• Finished Bridge

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Q A
Project Recognition

• Finalist for the ASCE Outstanding Civil
  Engineering Achievement award.
• Honors the project that best illustrates superior
  civil engineering skills and represents a
  significant contribution to civil engineering
  progress and society.
• First university student design project and first
  non-profit organization to receive this national
  nomination.

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Q A
Q A

• Questions?

Completed Bridge Painted in Guatemalas National
Colors