Concrete is used by contractors and builders for bridges and
seawalls due to its strength and durability. Unfortunately,
seawalls made of traditional concrete are not immune to the effects
of seawater, and bridges constructed of regular concrete are
proving to be incapable of withstanding the damaging winds and
forces of hurricanes and other strong storms.
However, Cor-Tuf Ultra-High Performance Concrete (UHPC)
is capable of withstanding hurricanes. This
marine-grade concrete also doesnât corrode or deteriorate in
seawater, making it the best material to use in seawall design and
construction.
The team at Cor-Tuf is dedicated to helping contractors and
designers benefit from our revolutionary concrete mix. We do not
believe that communities need to suffer from damage and destruction
to bridges, seawalls, and other concrete structures due to violent
storms and concrete salt damage.
A closer look at the durability of concrete in seawater and severe
storms
As we all know, seawalls are structures built parallel to the
shore to protect the shoreline from further erosion and wave
action. They also serve as a defense against coastal flooding and
storm surges. They are usually quite large in size, so they can
protect the mainland area from rising sea levels.
When building a seawall, the size, depth, and salinity of the
water is taken into account. Obviously, larger bodies of water and
those with stronger currents and tides demand stronger, more
durable seawall structures.
Water that is high in salinity will corrode traditional concrete
more quickly. Shorelines that get a lot of boat traffic are also
more susceptible to erosion and demand a more durable design.
Itâs also important to consider the impact of seawall
construction on the environment. Long construction times requiring
large machinery cause more damage to the surrounding
ecosystem.
Seawalls and bridges made of traditional concrete are strong and
have the potential to last more than 30 years. However, salt water
and concrete are like oil and vinegarâthey just donât mix.
There are several drawbacks to using regular concrete in seawall
and bridge construction that stem from the negative effects of
seawater on traditional concrete.
Corrosion
Traditional concrete is not impervious to water. The chloride
and sulfate ions in seawater get into the reinforced steel embedded
in the concrete and cause corrosion. Once exposed to the chloride
ions, other factors such as availability of oxygen, pH, and
temperature contribute to the rate at which corrosion occurs.
Additionally, when two different embedded metals within concrete
come into contact with each other, it can also cause corrosion as
one metal reacts with the other. The steel begins to rust, causing
it to expand. This, in turn, causes cracking and spalling in the
concrete structure.
Seawater also carries sand and silt, depositing these materials
onto concrete seawalls and bridges, causing abrasion (and further
deterioration).
Expansion and freezing
We all know water expands when it freezes. When water freezes
inside moist concrete, it creates pressure. If this pressure
becomes greater than the tensile strength of the concrete, it
results in expansion and cracking.
Deterioration of traditional concrete begins in as little as
28
freeze/thaw cycles. Adding to the problem,
deicing chemicals can actually exacerbate freeze/thaw damage,
as the salt in these mixtures absorbs moisture and makes the
concrete more saturated.
Severe coastal storms
In addition to damage from saltwater, coastal storms deliver
another blow to seawalls and bridges in the form of violent winds
and rising sea levels. As with most things in 2020, the hurricane
season is also shaping up to be
one for the record books. More storms have been named by this
point in the season than during any previous Atlantic hurricane
season.
Hurricanes inflict damage on all types of structures, and
concrete bridges are no exception. There have been some shocking
news stories demonstrating the damage strong storms can inflict on
traditional concrete bridges.
In Pensacola, Florida, an older bridge made of traditional
concrete had deteriorated from saltwater damage. It was being
replaced with a new bridge (again made of traditional concrete)
when Hurricane Sally hit. A portion of the bridge actually
collapsed due to the storm. Strong winds loosened construction
barges, which collided with the new structure. A short video of the
damage inflicted by the storm and barges can be seen here. An entire
section of the bridge was missing, resulting in more than 40 people
needing to be rescued.
The traditional methods of concrete construction are simply not
capable of holding up to the severity of hurricanes and other
natural disasters. We need a better solution.
Why Cor-Tuf UHPC is the only choice for bridge and seawall design
and construction
Cor-Tuf UHPC is a corrosion-resistant concrete that stands up to
the conditions of seawater and the pelting rain and gale-force
winds of hurricanes. While we have written about the use of Cor-Tuf
UHPC in bridge construction before, you may not be familiar with
our seawalls.
Our seawall system uses Cor-Tuf UHPC H-pilings. We cast a large,
solid sheet panel that slides between the two H-pilings, and a cap
is placed on top. Given the exceptional tensile strength of Cor-Tuf
UHPC H-pilings, our seawalls donât require buried tie-backs.
Since the wall is made entirely of Cor-Tuf UHPC, all of the
usual benefits of superior strength, durability, and flexibility
make these walls exceptional. The material is, without a doubt, the
best choice for bridge and seawall design and construction.
Why? Cor-Tuf UHPC Is:
- Impervious to waterâCor-Tuf UHPC is
moisture-resistant due to its higher density. This makes it almost
impossible for ordinary water to penetrate the surface.
- Salt water resistantâUHPC is a salt
water-resistant concrete, making it ideal for use in bridges,
seawalls, and other structures built in or near seawater.
- Freeze/Thaw resistantâUHPC has been shown to
withstand more than 1,000 freeze/thaw cycles and storms.
- Chemical resistantâUHPC does not deteriorate
when exposed to deicing solutions or sulfates.
UHPC can absorb three times greater energy than regular
concrete. With a compressive strength of 30,000 pounds per square
inch (psi), structures built with UHPC can withstand a greater
overload and have even been shown to
perform well in earthquake simulations.
Leveraging Cor-Tuf UHPC in both new bridge construction and in
bridge reconstruction and repair projects can reduce the damage
inflicted by strong winds, flying debris, and any other objects
that may collide or hit the bridge structure during a severe storm.
A stronger, more durable bridge not only saves lives, but also
decreases the costs associated with storm aftermaths.
But the advantages of Cor-Tuf UHPC donât stop there. When you
use Cor-Tuf UHPC for bridge and seawall construction, you also reap
the benefits of low-impact design and significant cost savings over
the life of a project.
Low-impact Design (LID)
The basis for the Cor-Tuf UHPC sea wall system consists of
driven H-pilings connected by thinner sheet piles that slide into
the gaps in the H slot on either side. When used alone, the system
represents a solution that requires minimal site disturbance and
zero excavation for additional tie-back support.
Your crew can show up on day one with little to no site prep and
start pounding H-pilings and panels into the ground. This is a
stark contrast to the typical scenario requiring extensive
excavation prior to installation.
The precast components used for UHPC bridge construction deliver
the same advantages of minimal site disturbance. Cor-Tuf UHPC is
part of a
sustainable bridge construction solution, helping to protect
natural resources, reducing energy consumption and waste, and
lowering a projectâs overall carbon footprint.
Cor-Tuf UHPC seawalls and bridges can also be installed using
smaller machinery and less equipment, since the components are
precast and lighter in weight. It becomes possible to go into
sensitive ecological areas that have stringent requirements and
install a seawall or bridge to protect humanity and the
environment.
Cost Savings
Cor-Tuf UHPC is lighter in weight and requires less footing and
support. As a result, fewer components are needed overall, more
components can fit on a truck, and fewer trucks are needed for
transport.
All of these elements add up to substantial critical path
savings. A condensed construction schedule saves time and resource
expenditure. The reduced maintenance requirements of Cor-Tuf UHPC
pile on the cost savings throughout the life of the structure.
We simply cannot afford to just react to storms only after they
happen. We need to take a proactive approach to storm protection.
The same applies to concrete structures in marine environments.
Structures not only need to last, but they also must be built in a
way that reduces the impact on the environment.
The team at Cor-Tuf UHPC is focused on sustainable solutions to
these issues. Our proprietary UHPC mix contains all of the
qualities needed to create bridges and seawalls that will stand up
against severe storms and the constant beating of seawater, and
they can be built using low-impact design. Now is the time to be
proactive in bridge and seawall construction, so we can save lives,
costs, infrastructure, and the environment.
The post
Cor-Tuf UHPC Seawall Construction: The Ultimate Defense for
Seawater and Storm Damage appeared first on Cor-tuf UHPC.
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