SEA WALLS

 seawall (or sea wall) is a form of coastal defense constructed where the sea, and associated coastal processes, impact directly upon the landforms of the coast. The purpose of a seawall is to protect areas of human habitation, conservation and leisure activities from the action of tides and waves.[1] As a seawall is a static feature it will conflict with the dynamic nature of the coast and impede the exchange of sediment between land and sea.

The coast is generally a high-energy, dynamic environment with spatial variations occurring over a wide range of temporal scales.[3] The shoreline is part of the coastal interface which is exposed to a wide range of erosional processes arising from fluvial, aeolian and terrestrial sources, meaning that a combination of denudational processes will work against a seawall.[4] Given the natural forces to which seawalls are constantly subjected, maintenance (and eventually replacement) is an ongoing requirement if they are to provide an effective long-term solution.

The many types in use today reflect both the varying physical forces they are designed to withstand, and location specific aspects, such as: local climate, coastal position, wave regime, and value of landform. Seawalls are classified as a hard engineering shore based structure used to provide protection and to lessen coastal erosion. However, a range of environmental problems and issues may arise from the construction of a seawall, including disrupting sediment movement and transport patterns, which are discussed in more detail below.[5] Combined with a high construction cost, this has led to an increasing use of other soft engineering coastal management options such as beach replenishment.

Seawalls may be constructed from a variety of materials, most commonly: reinforced concrete, boulders, steel, or gabions. Additional seawall construction materials may include: vinyl, wood, aluminium, fibreglass composite, and with large biodegrable sandbags made of jute and coir.[6] In the UK, sea wall also refers to an earthen bank used to create a polder, or adike construction.

Types

A seawall works by reflecting incident wave energy back into the sea, thereby reducing the energy and erosion which the coastline would otherwise be subjected to.[7] In addition to their unsightly visual appearance, two specific weaknesses of seawalls exist. Firstly, wave reflection induced by the wall may result in scour and subsequent lowering of the sand level of the fronting beach.[8] Secondly, seawalls may accelerate erosion of adjacent, unprotected coastal areas because they affect the littoral drift process.[9] The design and type of seawall that is appropriate depends on aspects specific to the location, including the surrounding erosion processes.[10] There are three main types of seawalls: vertical, curved or stepped, and mounds, as set out in the table:

Seawall types

Vertical seawalls are built in particularly exposed situations. These reflect wave energy. Under storm conditions a non-breaking standing wave pattern can form, resulting in a stationary clapotic wave which moves up and down but does not travel horizontally.[11][12] These waves promote erosion at the toe of the wall and can cause severe damage to the sea wall.[13] In some cases piles are placed in front of the wall to lessen wave energy slightly.

Curved or stepped seawalls are designed to enable waves to break to dissipate wave energy and to repel waves back to the sea. The curve can also prevent the wave overtopping the wall and provides additional protection for the toe of the wall.

Mound type seawalls, using revetments or riprap, are used in less demanding settings where lower energy erosional processes operate. The least exposed sites involve the lowest-cost bulkheads and revetments of sand bags or geotextiles. These serve to armour the shore and minimise erosion and may be either watertight or porous, which allows water to filter through after the wave energy has been dissipated.[14]

LINKS

https://drive.google.com/?authuser=0#folders/0By3ydFyW9LupeHE0Zzh4aFlpZ1k

Sample Report ( All rights reserved-do not copy)

Photos damaged sea wall

SAMPLE SEA WALL AND DOCK DRAWINGS- FOR ILLUSTRATION PURPOSES ONLY

What is involved in a structural inspection including a sea wall? click to follow the answer,

Explanation: There are many types, and different construction methodology for any particular sea wall, it all depends

on age, how well and maintained was the sea wall, concrete mix, if salt was introduced, design, was there any issues in soils, water infiltration,

hurricane, or rusted bars or concrete damage over the years the sea wall was built. So, it all depends

on many factors some we listed and some we did not.

No one knows for sure how long does an engineer plan to inspect a sea wall.  

There is a long answer and short one. The short answer it all depends on the sea wall condition,

such as footings, wall itself ( concrete wall, stone, sheet piles, or fiber glass), integrity, buckling

assessment, cracks, bending or shifting, failure or signs of failure. There are many cases where we an engineer may spend

(3) hours on simple structurally sound/good sea wall, and we have cases where an engineer may spend 1-2 weeks, and in some cases longer

time inspecting a badly collapsed sea wall. It all depends on the condition of sea wall. If a client is trying to know the condition

of the sea wall at this property, an engineer does not know for certainty before inspecting the sea wall in question. 

As part of a professional legal fiduciary duty and duty of due care, An engineer spends time necessary to analyze and test an existing 

structure such as a sea wall, there may be testing involved, testing of soils, concrete, or rebar, pressure testing, X-Ray, or GPR testing or possibly 

divers needed if issues are found below water level. The engineer for purposes of a proposal initially may guess based on  conversation with agents, contractors, or owners

or possibly review of photos of such sea wall, drawings, diagrams, or exhibits. If the sea wall looks good and as a start, an engineer may allow (3) hours, then see what 

happens after inspecting the sea wall. This is why we recommend Phase I inspection as a starting point, and if it was decided that an engineer needs to perform subsequent

follow up inspection and analysis of sea wall, then we go to phase II, and III. 

https://sites.google.com/site/structuralengineerflorida/general-information/structural-inspections

Few questions that clients or property owners may be asked are as follows: 

1) Do you know or have a reason to know that the sea wall at a certain property is

in bad or structurally deficient condition, and failed? also, 

2) do you know or have a reason to believe that certain soil or soil conditions caused damage or repairs are done or to be done to the sea wall? 

3) what is your main concern with sea wall>?

Seawalls in Southwest Florida have been collapsing and ripping away from backyards after being slammed by Hurricane Irma.

And if you live next to one, you probably know how challenging -- and costly -- repairs can be.