MASONRY CONNECTION 1

[Jandra11]

Hello guys, I have this project, a covered area(see the picture for reference)

the perimeter of this structure will be closed by masonry wall(9m height & 17m width. Here are my questions.
1) should I put a column besides the existing steel column and treat the proposed wall and its structural members independent to the existing structure?
2)If Im going to connect the masonry wall to the existing steel column, what are the things to consider and how to detail the connections?
3)Is there any design guide reference in British code that can help me understand more about this kind of project?

Any other suggestion will be very much appreciated

Thank you in advance.

 

[spieng89]

Why would you need to introduce a column into the design? Masonry can be built to that height with minimal extra effort.

Depending on your wind loading you may need to introduce bracing from the roof structure back to the wall to reduce the un-braced wall height.

Use vertically slotted connections between steel beams and cmu to allow steel to deflect without inducing stress on wall. Horizontal slotted connections at column

I'm not to familiar with British code

 

[Jandra11]

@spieng89 thank you for the response. so do you mean 9m height can be supported by lintel column only? with 200mm thick?.
The wind load consideration is around 1.5kPa.sorry but I didnt fully understand how to put the bracing, is it ok if you could provide a simple sketch and sample detailing of cmu connection to steel columns? and lintel beam to the steel column. thanks again

 

[jayrod12]

Why not go to 240 block, I don't think it would be reasonable to do 190 block 9m tall.

That steel structure seems like it would be extremely flexible, so unless you provided some significantly sized joints between the steel columns and the masonry walls, it's quite likely the new masonry walls will act like shearwalls for the steel structure.

 

[dik]

You are changing the loading on it. Is the existing building OK for the added lateral load?

Dik

 

[Jandra11]

thank you for the reponse

@jayrod we are going to proposed new columns at the perimeter of the structure please see attached file.

Do I still need to use 240 blocks?

@dik new column will be proposed to support the blockwall but there will be still additional lateral load based on our proposed detail. because we cannot put new column above the existing foundation. btw how should I connect the lintel beams to the existing steel column? Do I need to weld the rebars to the steel column?

 

[jayrod12]

The requirement for 240 blocks is based on wall height for me. Around here H/30 is conservative but comfortable which actually means you'd be most economical for rebate with 290 block, but I think 240 would work quite well. You're at H/45. I would bet you'd need reinforcing in every core.

 

[dik]

What is the column spacing in plan? You can introduce W8 or W10 at whatever spacing is required for lateral support, and have a sliding connection at the roof. Whatever, the added horizontal load at the roof has to be accommodated by your current lateral bracing system.

Dik

 

[BAretired]

Concrete block would not be my first choice of material to use in this situation. A better choice would be to add columns at mid point or third point of the 17m span, girts as required and decorative steel panels spanning vertically between girts.

If masonry must be used, it is better to add steel columns and girts spaced to keep the masonry thickness to a minimum. Sliding connections are not needed. If the masonry acts as a shear wall, so much the better.



BA

 

[Jandra11]

How about this proposal

@jayrod I limit the height by adding lintel beam at the midspan so I can use 150mm Blocks.

@dik 5meters maximum. and lintel column @ the middle of every span.But how do I connect lintel beam to steel column? or should I use concrete columns?

@Baretired thanks for the response.The client specified to used blockwall. Can you show me some sketch how to detail the connection between the block wall to steel column??

 

[BAretired]

There are a couple of details in the attached file which may be useful:

http://imiweb.org/masonry-detailing-series/

1. If the wall is centered on the existing columns, the steel frame (beam and columns) will be exposed to the weather. Steel will be more sensitive to temperature movement than block. Rigid connections may cause cracking of masonry. Perhaps it would be better to wrap the block around the steel frame.

2. Your elevation shows four proposed columns and three "lintel columns" at midspan. What is a lintel column? Why have two kinds of column? Decide on the required spacing and use one kind of column. It could be steel, concrete or masonry pilaster filled with concrete. For a 9m height, columns would need to be considerably deeper than the wall thickness.

3. I would suggest 190mm block to make room for reinforcement. One bond beam (it's not a lintel beam) at mid height is not enough. 1800mm sounds like a more comfortable spacing for bond beams.

BA

 

[BAretired]

That file didn't show the connection.

Here is one possible beam connection:

BA

 

[BAretired]

And this is a possible column connection:

http://imiweb.org/wp-content/uploads/2015/10/02.120.1102.jpg

BA

 

[dik]

With prefinished metal siding, BART offers a much better solution.

Dik

 

[Jandra11]

@baretired thank you so much.

My senior once told me the maximum area of masonry should be lesser than 15m2 so in order to divide the area we proposed lintel column/beam.

What is this bond beam?

 

[BAretired]

What is this bond beam?

Bond beams are commonly used in masonry walls. A bond beam consists of a row of lintel blocks, reinforced as required and filled with concrete. Use Google to find more about bond beams:

https://www.google.com/search?q=mas...7AkIMg&biw=1280&bih=610#imgrc=03qlDeQJT0jcNM:

Your detail of "LINTEL/STIFFENER COLUMN" shows a solid concrete column 300 x t where t = wall thickness. You were proposing t = 150mm which is much too flexible for a 9000mm height.

As I said before, you should use one type of column which is capable of spanning 9m. If it is a steel column, you may be looking at a 250mm or 300mm deep I section in order to control deflection. Columns should be spaced such that your wall can span horizontally between them.

Having said all that, prefinished metal siding would be a more attractive and more economical solution than masonry walls. Why not suggest it to your client?

BA

 

[dhengr]

Jandra11:
BA’s got the right idea, 4JUL18, 18:12, with girts and stl. siding. Well informed and experienced engineers are entitled to suggest practical and economical alternatives to their clients, even though the client was born with the idea that fig leaves would make a wonderful exterior cladding. It falls to us to explain why this is practical and economical. You are trying to mix a very flexible steel structural system which has apparently taken gravity and lateral loads, with a very rigid conc. blk. system, and they do not marry well, except with some difficult detailing, etc. You may have to reinforce the stl. cols. and beams for the greatly increased lateral loading of the completely enclosed bldg. but that may still be the easier, cleaner solution. If you go with the conc. blk. wall approach, try to use std. blks., lintel blks. on their sides, 16” deep lintels standing vertically, pilasters around stl. cols. etc., many to be grouted and reinforced. The full thickness conc. vert. member, which you show, requires reinforcing and forming after the wall is layed, and that is kinda an extra step or trade which adds complexity.