Chirajara Bridge - Revision history

Sakowski at 07:36, 6 October 2023

2023-10-06T07:36:39Z

Sakowski at 07:07, 6 October 2023

2023-10-06T07:07:46Z

Sakowski at 05:11, 6 December 2022

2022-12-06T05:11:17Z

Sakowski at 05:10, 6 December 2022

2022-12-06T05:10:46Z

Sakowski at 05:08, 6 December 2022

2022-12-06T05:08:28Z

Sakowski at 05:01, 6 December 2022

2022-12-06T05:01:13Z

Sakowski at 04:58, 6 December 2022

2022-12-06T04:58:28Z

Sakowski at 04:45, 6 December 2022

2022-12-06T04:45:54Z

Sakowski at 03:59, 6 December 2022

2022-12-06T03:59:38Z

Sakowski at 03:46, 6 December 2022

2022-12-06T03:46:55Z

@@ Line 83: / Line 83: @@
 [[File:Viaducto ChirajaraOldBeamValley.jpg|750px|center]]
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 [[File:Puente-Chirajara-render.jpg|750px|center]]
 Original Chirajara Bridge render with the diamond shaped towers.

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 foot span / 192 meter span<br />
 <br />
-[[File:ChirajaraNew 114.6+192+114.6.jpeg|750px|center]]
+[[File:Viaducto ChirajaraCreek.jpg|750px|center]]
 </div>
@@ Line 59: / Line 59: @@
 Old Chirajara Bridge Elevation<br />
 </div>
 [[File:ChirijaraComponents.jpg|900px|center]]
 [[File:Newviaducto-Chirajara.jpg|750px|center]]

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 The new beam design came after a V-shaped cable stayed configuration was scrapped as the replacement for the original diamond shaped cable stayed tower that collapsed in 2018.  This accident forever tarnished the once perfect track record of zero cable stayed bridge collapses stretching back more then 60 years to the first modern cable stayed span from 1957.
-On January 15, 2018, the entire west side of the nearly finished Chirajara Bridge collapsed into the gorge killing 10 construction workers.  After an investigation, engineers discovered that the horizontal connection within the diamond-shaped towers was insufficiently designed with a minimal number of prestressing cables.  Incorrect calculations were also made about the lateral strength of the concrete diaphragm wall that connected the lower V-shaped legs of the towers.  The study of the bridge collapse is detailed in an excellent IABSE paper written by Dr. Christos T. Georgakis, Dr. Yozo Fujino, Siegfried Hopf, Klaus H. Ostenfeld and Dr. S. Eilif Svensson.
+On January 15, 2018, the entire west side of the nearly finished Chirajara Bridge collapsed into the gorge killing 9 construction workers.  After an investigation, engineers discovered that the horizontal connection within the diamond-shaped towers was insufficiently designed with a minimal number of prestressing cables.  Incorrect calculations were also made about the lateral strength of the concrete diaphragm wall that connected the lower V-shaped legs of the towers.  The study of the bridge collapse is detailed in an excellent IABSE paper written by Dr. Christos T. Georgakis, Dr. Yozo Fujino, Siegfried Hopf, Klaus H. Ostenfeld and Dr. S. Eilif Svensson.
 Normally the cross tie beams in a concrete cable stayed bridge tower are at least 2 meters thick with several rows of prestressing cables.  For the Chirajara Bridge the cross tie was just .6 meters thick with only one row of 12 prestressing cables holding the two sides of the tower together.

← Older revision		Revision as of 05:10, 6 December 2022
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−	Chirajara Bridge is the highest bridge in Colombia with a deck ~~150~~ meters above a forested creek that flows into the great Rio Negro River gorge along the Bogota-Villavicencio highway. Originally to be a cable stayed bridge, the final design is a cantilevered concrete beam bridge with a total length of 460 meters with a span configuration of 114.6 +192 +114.6 meters on piers 73 and 54 meters tall.	+	Chirajara Bridge is the highest bridge in Colombia with a deck 156 meters above a forested creek that flows into the great Rio Negro River gorge along the Bogota-Villavicencio highway. Originally to be a cable stayed bridge, the final design is a cantilevered concrete beam bridge with a total length of 460 meters with a span configuration of 114.6 +192 +114.6 meters on piers 73 and 54 meters tall.

	The new beam design came after a V-shaped cable stayed configuration was scrapped as the replacement for the original diamond shaped cable stayed tower that collapsed in 2018. This accident forever tarnished the once perfect track record of zero cable stayed bridge collapses stretching back more then 60 years to the first modern cable stayed span from 1957.		The new beam design came after a V-shaped cable stayed configuration was scrapped as the replacement for the original diamond shaped cable stayed tower that collapsed in 2018. This accident forever tarnished the once perfect track record of zero cable stayed bridge collapses stretching back more then 60 years to the first modern cable stayed span from 1957.

@@ Line 26: / Line 26: @@
 Sadly the Chirajara Bridge disaster would not be the last cable stayed accident in 2018 as on August 14 a tower and span of the Morandi cable stayed bridge in Genoa, Italy collapsed from excessive corrosion of the wire stays.
-CHIRAJARA BRIDGE CRITICAL DEFICIENCIES
+CHIRAJARA CABLE STAYED BRIDGE CRITICAL DEFICIENCIES
 . A severe lack of bracing tie capacity of the link slab and diaphragm was found for design loads, service loads, and during erection. The lack of bracing was the main deficiency leading to the eventual collapse of Pylon B and the bridge as a whole.
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 . A lack of reinforcement was found in the longitudinal direction for the girder concrete slab, in regions with large negative moments. The specified transverse reinforcement was insufficient when considering transfer of shear between steel girder and concrete slab.
-CHIRAJARA BRIDGE SECONDARY DEFICIENCIES
+CHIRAJARA CABLE STAYED BRIDGE SECONDARY DEFICIENCIES
 . Sufficient structural capacity during construction and for service loads was found for the caisson. A slight excess of shear capacity was found for design loads. This could be rectified by applying actual material strengths instead of considering design values.

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 . The bearing layout at pylons and abutments would result in a “floating” statical system. An unproven solution that among other things would induce large stresses in parts of the structure with incomplete direction and without respect for the flow of forces in the complete system. The bearings would not have sufficient capacity to withstand the expected shear forces and deformations during construction and for the service stage design loads, resulting in excessive shear deformations with potential failure.
-. Considerable redesign and retrofit of the anchor beam assembly would be needed to accommodate the design loads in the service stage. Deficiencies were found regarding the formation of local plastic hinges resulting in instability, in- sufficient lateral reinforcement at top face, and missing shear connectors between steel I-beams and encasing concrete to provide composite action. Most importantly, the bearing design related to the transition beam would need a complete redesign.
+. Considerable redesign and retrofit of the anchor beam assembly would be needed to accommodate the design loads in the service stage. Deficiencies were found regarding the formation of local plastic hinges resulting in instability, insufficient lateral reinforcement at top face, and missing shear connectors between steel I-beams and encasing concrete to provide composite action. Most importantly, the bearing design related to the transition beam would need a complete redesign.
 . Longitudinal force components would create bending and high local shear stresses in the front and back wall of the pylon head since no bracing with sufficient shear capacity was provided inside the pylon head to transfer horizontal and vertical components of stay forces to the pylon head concrete walls.

@@ Line 38: / Line 38: @@
 . The transition beam and corresponding connections were found to be inadequate and not designed with proper tensile capacity.
-. As designed, the longitudinal edge beams of the girder would experience a sig- nificant exceedance of allowable stresses in the bottom flange, due to negative bending at the pylon supports for service stage design loads. Overstress in the top flange was found at mid-span for transverse bending moments caused by design wind loads at service stage. Shear resistance of the web was found to be insufficient, and the web would be prone to buckling instability, even with the provided stiffening.
+. As designed, the longitudinal edge beams of the girder would experience a significant exceedance of allowable stresses in the bottom flange, due to negative bending at the pylon supports for service stage design loads. Overstress in the top flange was found at mid-span for transverse bending moments caused by design wind loads at service stage. Shear resistance of the web was found to be insufficient, and the web would be prone to buckling instability, even with the provided stiffening.
 . A lack of reinforcement was found in the longitudinal direction for the girder concrete slab, in regions with large negative moments. The specified transverse reinforcement was insufficient when considering transfer of shear between steel girder and concrete slab.

← Older revision		Revision as of 04:45, 6 December 2022
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	[[File:ChirajaraCloseTowerBase.jpg\|750px\|center]]		[[File:ChirajaraCloseTowerBase.jpg\|750px\|center]]
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		+	[[File:ChirijaraPylonGround.jpg\|750px\|center]]
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		+	[[File:ChirajaraSeparation.jpg\|750px\|center]]
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		+	[[File:ChirijaraCrossTieBreak.jpg\|750px\|center]]
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		+	[[File:ChirijaraOffCenterDucts.jpg\|750px\|center]]
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		+	[[File:ChirijaraDuctsOffset.jpg\|750px\|center]]

← Older revision		Revision as of 03:59, 6 December 2022
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−	[[File:ChirijaraSpreadOutForces.jpg\|~~900px~~\|center]]	+	[[File:ChirijaraSpreadOutForces.jpg\|750px\|center]]
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		+	[[File:ChirijaraNoTensionTie.jpg\|750px\|center]]

← Older revision		Revision as of 03:46, 6 December 2022
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	Old Chirajara Bridge Elevation<br />		Old Chirajara Bridge Elevation<br />
	</div>		</div>
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		+	[[File:ChirijaraComponents.jpg\|900px\|center]]