seawall

[v2]

Is it ok to attach the 2nd floor slab of the building to the top of an existing freestanding seawall that is about 8 to 9 ft tall?

the building is 11 story high on the ocean shoreline in florida.

thanks V2

 

[DaveVikingPE]

NO.

 

[FM1]

NO.

 

[Lutfi]

NO. You are asking for trouble. One simple reasone is that the sea wall is free and will deflect at top. If you restrain it them you will change the boundary conditions. I am concerned that your are considering this for an 11 story building. I would recommend deep foundations.

Good luck.

 

[tamu]

Is it canopy slab of two floor height? Do not take support of not only of sea wall but even existing 11 storey structure too i.e. have independent structure for proposed slab.

 

[v2]

the building sets back about 45 feet from seawall. only the 2nd floor slab connects to the top of the wall. the second floor slab outside the building is a recreation deck with landscaping and a swimming pool.
thanks. V2

 

[DaveVikingPE]

It is good to have more information.

What are the wind and wave forces on the seawall? Why does the deck have to attach to the seawall?

 

[v2]

Below the deck and behind the seawall is a parking garage. I am not sure what the wave forces are. The building is on the east coast of Florida. Wind pressure is probably 80 to 90 psf.
That is all I know. I have not seen the drawings for the existing seawall yet. So I really do not know what the exact structure is. But I was told that it is designed for a 100 years recurrence.
V2

 

[Lutfi]

ASCE 7 has a section on computing the wave action. I live and work on the east coast of Florida. If you are that close to the beach, wave-braking force must be considered and also scour effects!!

Still I do not like the idea of supporting floors on the sea wall.

 

[austim]

Hi, V2.

If you 'connect' the top of the seawall to your building with any structure that restrains the lateral deflection of the seawall at its top, you will radically alter the distribution of bending moments in the wall. Quite possibly you will generate vertical tensions in the shoreward face of the wall which could easily exceed the capacity of the wall reinforcement.

On the other hand, if your 'connection' to the wall is via properly designed expansion bearings which will transfer vertical loads only, but leave the wall entirely free to deflect under wave loads, then you might have a viable scheme. But even then you will need to reanalyse the seawall for the effects of the added vertical loadings.

 

[v2]

The seawall has a ledger at the top. Whoever engineered it presumably must have anticipated vertical gravity loads in the plane of the wall with some eccentricity.

Thanks for your comments.


V2