Steel ring beam supported by rebars of concrete column

[citi]

In Thailand, the ring steel beam is normally supported by rebars of the column for roof truss as shown in the diagram 1. Do any TV members use base plate, anchor bolts and grouting as the supporting contact between steel beam and the concrete as shown in diagrams 2 and 3? If yes, please post some photos for my roof design of future house extension.

Diagram 2.bmp

[IMHO]

Our builders do it like this:

1. Trim the cement post down to the correct height (leaving rebar poking out the top)

2. Using a 10mm thick steel plate, drill 4 holes at rebar spacing then slide it down flush with the top of the post, then weld the rebar to the plate

3.Trim the rebar

4. Weld the roof truss to the plate

Our guys always pour the posts a little tall, the use an angle grinder to trim them down exact - so nothing like your diagram #1 - the end result is close to your diagram 2, but the plate is welded on instead of screwed, and no gap filling is required.

[citi]

Our builders do it like this:

1. Trim the cement post down to the correct height (leaving rebar poking out the top)

2. Using a 10mm thick steel plate, drill 4 holes at rebar spacing then slide it down flush with the top of the post, then weld the rebar to the plate

3.Trim the rebar

4. Weld the roof truss to the plate

Our guys always pour the posts a little tall, the use an angle grinder to trim them down exact - so nothing like your diagram #1 - the end result is close to your diagram 2, but the plate is welded on instead of screwed, and no gap filling is required.

Thank you for your input. I believe that the method of your builder is like diagrams 4 & 5. His method is very close to mine but I prefer to use anchor bolts as shown in diagrams 6 & 7 for easy levelling. After levelling, the gap is filled with grouting material for force transmission from the weight of roof truss to concrete column. However, the method of your builder is good enough if his skill is good for levelling and concrete filling. I hope our discussion is useful to other TV members because this problem of connection of steel ring beam to concrete column bothers me for a long time.

[IMHO]

Our builders do it like this:

1. Trim the cement post down to the correct height (leaving rebar poking out the top)

2. Using a 10mm thick steel plate, drill 4 holes at rebar spacing then slide it down flush with the top of the post, then weld the rebar to the plate

3.Trim the rebar

4. Weld the roof truss to the plate

Our guys always pour the posts a little tall, the use an angle grinder to trim them down exact - so nothing like your diagram #1 - the end result is close to your diagram 2, but the plate is welded on instead of screwed, and no gap filling is required.

Thank you for your input. I believe that the method of your builder is like diagrams 4 & 5. His method is very close to mine but I prefer to use anchor bolts as shown in diagrams 6 & 7 for easy levelling. After levelling, the gap is filled with grouting material for force transmission from the weight of roof truss to concrete column. However, the method of your builder is good enough if his skill is good for levelling and concrete filling. I hope our discussion is useful to other TV members because this problem of connection of steel ring beam to concrete column bothers me for a long time.

Yep, similar to diagram 4 & 5, but without the gap to be filled as the top of the post has already been levelled the the correct height by power tools and sweat

All of our builders do it this way - I guess it must be one of dad's specs. I'm not active in the family business so only know what I've seen

[Crossy]

Our ring beams are concrete with a relatively small steel beam on top to support the roof components.

This post http://www.thaivisa.com/forum/topic/481794-housebuilding-thread/?p=4959975 shows how it hangs together, it's not come off yet.

The 'mysterious welded objects' were levelled and attached to the column steel before the ring beams were poured.

[citi]

Our ring beams are concrete with a relatively small steel beam on top to support the roof components.

This post http://www.thaivisa.com/forum/topic/481794-housebuilding-thread/?p=4959975 shows how it hangs together, it's not come off yet.

The 'mysterious welded objects' were levelled and attached to the column steel before the ring beams were poured.

Thanks. Recently, the new house uses concrete ring beam instead of steel ring beam. From my internet research, there are many methods to attach roof truss to concrete ring beam, namely angle brackets, pre-cast rebar (coming out from concrete ring beam) and your builder's method. For my project, I plan to build an extension at the back of my house for a kitchen (11m x 4m). Installation of concrete ring beam is more expensive and heavier as compared with steel ring beam. Now I have fairly a good idea how to design the connection between steel ring beam and concrete column. If I have completed my renovation, I shall post the photos for reference.

[IMHO]

Our ring beams are concrete with a relatively small steel beam on top to support the roof components.

This post http://www.thaivisa.com/forum/topic/481794-housebuilding-thread/?p=4959975 shows how it hangs together, it's not come off yet.

The 'mysterious welded objects' were levelled and attached to the column steel before the ring beams were poured.

Thanks. Recently, the new house uses concrete ring beam instead of steel ring beam. From my internet research, there are many methods to attach roof truss to concrete ring beam, namely angle brackets, pre-cast rebar (coming out from concrete ring beam) and your builder's method. For my project, I plan to build an extension at the back of my house for a kitchen (11m x 4m). Installation of concrete ring beam is more expensive and heavier as compared with steel ring beam. Now I have fairly a good idea how to design the connection between steel ring beam and concrete column. If I have completed my renovation, I shall post the photos for reference.

Yep, concrete ring beams are the standard in 2/3 storey homes, but also used in single storey homes if the roof design presents loading challenges, or the architect designed it to BKK specs... Most common method of attaching trusses to concrete ring beams is simply rebar tied into the ring beam itself - I can't see any reason why you'd need more strength than that given the surface area of the connection and the sheer number of rebars you could use..