Lintol with narrow pier at one end 1

[philipquilty]

I am sizing lintols for a friend who is planning a house extension.
He wants to create a wide opening in the existing rear elevation. The width of masonry remaining either side of opening will be 600mm one end but only 300mm other end (basically thickness of cavity gable wall perpendicular to rear elevation).
BS 5977-1 'Lintels - Method for assessment of load' Clause 5e requires masonry either side to be 600mm or 0.2 x clear span, whichever is greater.
Do I just have to design lintol to carry FULL vertical loading rather than load triangle and any loads in interaction zone ie. no arching action? What checks do I need to make regarding strength and stability of remaining narrow brick pier?
Many thanks for any advice offered.

 

[asixth]

With 300 wide one end you are only going to have 1 grouted cell. I think the best way would be to have the one grouted cell and place a 3-4" steel tube to take the lintel. Make sure you have lateral restraint to the lintel and jamb.

 

[frv]

You really need to consult a structural engineer.

 

[philipquilty]

I am a civil engineer and have been trained in structures but rarely get involved with masonry design/checking.

 

[frv]

I graduated from civil but wouldn't dare design any storm sewers at this point.

Asking "what checks" you needed to do led me to believe you didn't know what you were doing. Just because you took a class in it, doesn't mean you are "trained" in it. If you know what you are doing, good for you. I just get nervous when someone asks a blanket question about what they need to check; It's almost the same as saying "how do I do this"?

 

[philipquilty]

Thanks frv,
I know I need to assess the slenderness of the pier and calculate its load capacity and also the overturning and shear strength for any horizontal loading. I was hoping for a steer to the appropriate parts of BS 5628 (hardly familiar with this let alone Eurocode). Is it a non starter though/pier likely to be just too narrow? What about my question regards non-arching action/full vertical loading? I am minded to tell my friend that he can't have such a narrow pier and has to have a 300mm return at each end ie. 600mm from outside face of return walls - or is that a cop out?