Since I last reported on damage to the Tree Lane Bridge over Ben’s Branch in January, the situation has worsened considerably.
- Concrete reinforcements under and on both sides of the bridge have collapsed from undercutting, erosion and jetting.
- The stream has downcut, exposing pipelines.
- Jetting has carved out a cavernous area south of the bridge.
- Erosion has reached within a few feet of a utility corridor.
- Storm sewer outfalls have been exposed, undercut and punctured by massive slabs of displaced concrete.
- Bridge supports, once protected by sidewalls, have been exposed to more erosion.
Pictures Taken on 6/12/23 Show Extent of Damage
The bridge will probably not collapse in the next big rain. However, the cumulative damage to all these components underscores the need for urgent repair. It also underscores the need for mitigation to reduce the jetting that caused the damage.
Damage Accelerating, Repaired Just Three Years Ago
The city repaired the Tree Lane Bridge in March of 2020. Compare this post to see how it looked then. It’s amazing how much damage could be done in three years to a bridge that weathered multiple hurricanes and tropical storms for more than 50 years.
That’s a testament to insufficiently mitigated development upstream that sends ever greater volumes of water downstream – more than the opening under the bridge was designed for.
For a description of how jetting works, check this post. Basically, water backs up behind the bridge, putting greater pressure on the water flowing under the bridge.
Let’s hope the City can repair the Tree Lane Bridge again before school starts in the fall. The bridge borders Bear Branch Elementary School where 638 students attend classes.
Please check bridges near you and report any damage.
Posted by Bob Rehak on 6/12/2023
2113 Days since Hurricane Harvey