ASCE 7-10 Chapter 14 Masonry Detailing
ASCE 7-10 Chapter 14 Masonry Detailing
(OP)
In reviewing Masonry detailing for a project slated to have special reinforced masonry shearwalls in SDC D i have come across a detailing provision that requires no lap splices or weleded splices within the plastic hinge zone of a Special Reinforced Masonry Shearwall.
ASCE 7-10 section 14.4.4.2.2 stipulates no splicing, except mechanical type II in plastic hinge zones. and they define the hinge zone as 15% of the distance btw zero and maximum moment. which for most buidlings would be the base of the wall.
IBC 2012 has a similar requirement in the strength design provision alterations. in ASD they require a 50% increase if stress is above 80% in reinf.
Typically footings would have dowels matching the vertical bar spacing and size. This dowel is lapped with the vertical bars in the plastic hinge zone, apparently.
Does the ASCE 7 provison aiim to eliminate this type of detailing? Does the Dowel from the footing need to be long enough to reach above the plastic hinge zone or have a mechanical type II coupler to the wall reinf.? I don't see this currently being done on jobs i have seen in construction.
Any input is appreciated. or loopholes to this requirement to explain what i currently see being done everywhere.
ASCE 7-10 section 14.4.4.2.2 stipulates no splicing, except mechanical type II in plastic hinge zones. and they define the hinge zone as 15% of the distance btw zero and maximum moment. which for most buidlings would be the base of the wall.
IBC 2012 has a similar requirement in the strength design provision alterations. in ASD they require a 50% increase if stress is above 80% in reinf.
Typically footings would have dowels matching the vertical bar spacing and size. This dowel is lapped with the vertical bars in the plastic hinge zone, apparently.
Does the ASCE 7 provison aiim to eliminate this type of detailing? Does the Dowel from the footing need to be long enough to reach above the plastic hinge zone or have a mechanical type II coupler to the wall reinf.? I don't see this currently being done on jobs i have seen in construction.
Any input is appreciated. or loopholes to this requirement to explain what i currently see being done everywhere.





RE: ASCE 7-10 Chapter 14 Masonry Detailing
FEMA P-750's commentary to ASCE 7 may be useful
RE: ASCE 7-10 Chapter 14 Masonry Detailing
IBC 2012 Chapter 21 (Masonry) 2107 and 2108 give some added provisions for lap splices.
In ASD 2107 notes the 72 db max as you mention, but also gives the 50% increase if stress is more than 80%
In Stength Design section 2108 notes no welded splices or type I mechanical in plastic hinge zone but actually doesn't limit lap splices. so i guess that is why they are still being used typically.
Your FEMA reference is interesting as well, i guess that is why the building code has chosen not to adopt the provision. However in concrete walls the laps are increased in the expected areas of yeilding (hinge zones) 25%, seems like this would be replicated in masonry walls if the RC analogy is going to be utilized. Also, RC walls typically have confining ties on boundary zones where yeilding will occurs so the long bars are much more confined than in a masonry wall.
RE: ASCE 7-10 Chapter 14 Masonry Detailing
Thanks,