780 CMR, CHAPTER 16

Current through Register 1536, December 6, 2024

Chapter CHAPTER 16 - STRUCTURAL DESIGN

1603.1.7 Revise subsection as follows:

1603.1.7Flood Design Data. For buildings located in whole or in part in flood hazard areas as established in section 1612.3, the documentation pertaining to design, if required in section 1612.5, shall be included and the following information, referenced to the datum of the base flood elevation, shall be shown, regardless of whether flood loads govern the design of the building:

1. Flood design class assigned according to ASCE 24.

2. In flood hazard areas other than coastal high hazard areas or the elevation of the proposed lowest floor, including the basement.

3. In flood hazard areas other than coastal high hazard areas or the elevation to which any nonresidential building will be dry floodproofed.

4. In coastal high hazard areas the proposed elevation of the bottom of the lowest horizontal structural member of the lowest floor, including the basement.

1604.11 and Table 1601.11 Add section and table as follows: 1604.11 Snow, Wind and Earthquake Design Factors. Ground snow load, pg, basic wind speed, V, and earthquake response accelerations for the maximum considered earthquake, SS and S1, for each city and town in the Commonwealth shall be as given in Table 1604.11.

TABLE 1604.11 SNOW LOADS, WIND SPEEDS, AND SEISMIC PARAMETERS

	SNOW	LOADS	BASIC	WIND	SPEED,	V4 (mph)	SEISMIC PARAMETERS (g)		PEAK GROUND ACCELERATION
City/Town	Ground Snow Load, Pg (psf) / Mean Elevation (feet)	Minimum Flat Roof Snow Load, Pf1 (psf)	Risk Category I	Risk Category II	Risk Category II	Risk Category IV	Ss	S1	Pga
Abington	35	30	113	123	131	136	0.224	0.059
Acton	50	35	108	117	126	130	0.302	0.070
Acushnet	30	30	120	129	138	142	0.192	0.053
Adams2	603/1535	40	104	111	119	125	0.168	0.058
Agawam	35	35	106	115	124	129	0.168	0.055
Alford2	40	40	104	112	120	125	0.165	0.055
Amesbury	50	30	107	116	125	129	0.356	0.077
Amherst	40	35	105	114	123	128	0.171	0.057
Andover	50	30	108	117	126	130	0.355	0.076
Aquinnah (Gay Head)	25	25	124	134	143	147	0.161	0.048
Arlington	40	30	109	119	128	132	0.286	0.067
Ashburnham	603/1151	35	106	114	123	128	0.288	0.069
Ashby	603/929	35	106	114	123	128	0.333	0.074
Ashfield	503/1338	40	104	112	120	126	0.167	0.057
Ashland	40	35	109	119	128	132	0.235	0.062
Athol	60	35	105	113	122	127	0.211	0.062
Attleboro	35	30	114	124	132	137	0.206	0.057
Auburn	50	35	108	118	127	131	0.199	0.058
Avon	35	35	112	123	131	136	0.226	0.060
Ayer	50	35	107	116	125	129	0.322	0.072
Barnstable	30	25	122	130	138	144	0.160	0.049
Barre	503/893	35	106	115	124	129	0.202	0.060
Becket2	603/1566	40	104	113	120	125	0.162	0.055
Bedford	50	30	108	118	127	131	0.309	0.070
Belchertown	40	35	106	115	124	129	0.173	0.056
Bellingham	40	35	110	121	129	134	0.209	0.058
Belmont	40	30	109	119	128	132	0.280	0.067
Berkley	30	30	116	126	135	139	0.204	0.055
Berlin	50	35	108	117	127	131	0.246	0.064
Bernardston	60	35	104	112	120	126	0.183	0.060
Beverly	50	30	109	119	127	132	0.312	0.070
Billerica	50	30	108	117	126	130	0.333	0.073
Blackstone	40	35	111	121	130	135	0.203	0.057
Blandford	503/1273	40	105	114	122	127	0.162	0.055
Bolton	50	35	108	117	126	130	0.273	0.067
Boston	40	30	110	120	128	133	0.270	0.065
Bourne	30	25	120	129	137	142	0.180	0.052
Boxborough	50	35	108	117	126	130	0.296	0.069
Boxford	50	30	108	117	126	130	0.354	0.076
Boylston	50	35	108	117	126	130	0.229	0.062
Braintree	35	30	112	122	130	135	0.238	0.061
Brewster	25	25	122	130	139	145	0.150	0.048
Bridgewater	30	30	115	125	133	138	0.210	0.057
Brimfield	40	35	108	117	126	131	0.177	0.056
Brockton	35	30	113	123	132	137	0.220	0.059
Brookfield	50	35	108	117	126	130	0.184	0.057
Brookline	40	30	110	120	128	133	0.263	0.065
Buckland2	60	40	104	112	120	125	0.169	0.058
Burlington	50	30	108	118	127	131	0.314	0.071
Cambridge	40	30	110	120	128	133	0.272	0.066
Canton	40	35	111	122	130	135	0.231	0.060
Carlisle	50	30	108	117	126	130	0.320	0.072
Carver	30	30	117	127	135	140	0.198	0.055
Charlemont2	603/987	40	104	112	120	125	0.169	0.058
Charlton	50	35	109	118	127	131	0.187	0.057
Chatham	25	25	124	132	140	146	0.140	0.046
Chelmsford	50	30	108	117	125	130	0.346	0.075
Chelsea	40	30	110	120	128	133	0.278	0.066
Cheshire2	603/1453	40	104	112	119	125	0.167	0.057
Chester	60	40	105	113	121	126	0.162	0.055
Chesterfield	503/1165	40	105	113	121	126	0.164	0.056
Chicopee	35	35	106	115	124	129	0.167	0.055
Chilmark	25	25	125	134	143	147	0.158	0.047
Clarksburg2	603/1504	40	104	111	119	125	0.171	0.059
Clinton	50	35	108	117	126	130	0.257	0.065
Cohasset	35	30	112	122	130	136	0.239	0.061
Colrain2	60	40	104	112	120	125	0.175	0.059
Concord	50	35	108	118	127	131	0.297	0.069
Conway	50	40	104	113	121	126	0.169	0.057
Cummington2	603/1396	40	104	113	120	126	0.164	0.056
Dalton2	603/1527	40	104	112	120	125	0.165	0.057
Danvers	50	30	109	118	127	132	0.322	0.071
Dartmouth	30	30	120	129	138	142	0.191	0.053
Dedham	40	35	110	120	129	134	0.244	0.062
Deerfield	50	35	105	113	121	126	0.174	0.058
Dennis	30	25	122	130	138	144	0.156	0.049
Dighton	30	30	116	126	135	139	0.202	0.055
Douglas	40	35	110	120	129	133	0.196	0.057
Dover	40	35	110	120	129	134	0.240	0.062
Dracut	50	30	107	116	125	129	0.371	0.078
Dudley	50	35	109	119	128	133	0.186	0.056
Dunstable	50	35	107	115	124	129	0.375	0.078
Duxbury	30	30	115	125	133	138	0.206	0.056
E. Bridgewater	35	30	114	124	133	137	0.214	0.058
E. Brookfield	50	35	108	117	126	130	0.188	0.058
E. Longmeadow	35	35	107	116	125	130	0.171	0.055
Eastham	25	25	122	130	139	144	0.150	0.048
Easthampton	40	35	105	114	123	128	0.165	0.056
Easton	35	30	113	123	131	136	0.219	0.059
Edgartown	25	25	125	134	143	147	0.151	0.047
Egremont2	40	40	104	112	120	125	0.165	0.055
Erving	50	35	105	113	121	126	0.182	0.059
Essex	50	30	109	118	127	132	0.321	0.071
Everett	40	30	109	119	128	133	0.283	0.067
Fairhaven	30	30	120	130	138	143	0.189	0.052
Fall River	30	30	118	128	136	140	0.198	0.054
Falmouth	30	25	122	131	140	145	0.168	0.049
Fitchburg	60	35	106	115	124	128	0.300	0.070
Florida2	603/1784	40	104	111	119	125	0.169	0.058
Foxborough	35	35	112	122	131	136	0.215	0.058
Framingham	40	35	109	119	128	132	0.241	0.063
Franklin	40	35	111	121	130	135	0.213	0.058
Freetown	30	30	117	127	135	139	0.201	0.055
Dover	40	35	110	120	129	134	0.240	0.062
Dracut	50	30	107	116	125	129	0.371	0.078
Gardner	603/1073	35	106	114	123	128	0.252	0.066
Georgetown	50	30	108	117	125	130	0.356	0.076
Gill	50	35	104	113	120	126	0.185	0.060
Gloucester	50	30	109	119	128	132	0.305	0.070
Goshen	503/1349	40	104	113	121	126	0.165	0.056
Gosnold	30	25	123	132	142	146	0.174	0.050
Grafton	50	35	109	119	128	132	0.211	0.059
Granby	35	35	106	114	123	128	0.168	0.056
Granville	50	40	106	114	123	128	0.165	0.054
Great Barrington2	50	40	104	113	120	125	0.164	0.055
Greenfield	50	35	104	113	120	126	0.176	0.058
Groton	60	35	107	116	125	129	0.343	0.075
Groveland	50	30	108	116	125	130	0.361	0.077
Hadley	40	35	105	114	123	128	0.169	0.056
Halifax	30	30	116	125	134	138	0.209	0.057
Hamilton	50	30	109	118	127	131	0.326	0.072
Hampden	35	35	107	116	126	130	0.172	0.055
Hancock2	503/1595	40	104	111	119	124	0.171	0.057
Hanover	35	30	114	124	132	137	0.221	0.059
Hanson	35	30	114	124	132	137	0.216	0.058
Hardwick	50	35	107	115	125	129	0.184	0.058
Harvard	50	35	107	116	125	130	0.298	0.070
Harwich	25	25	123	131	139	146	0.146	0.047
Hatfield	40	35	105	114	122	127	0.168	0.056
Haverhill	50	30	107	116	125	129	0.369	0.078
Hawley2	603/1482	40	104	112	120	125	0.167	0.057
Heath2	603/1526	40	104	112	120	125	0.171	0.058
Hingham	35	30	112	122	130	135	0.239	0.061
Hinsdale2	603/1591	40	104	112	120	125	0.164	0.056
Holbrook	35	30	112	123	131	136	0.229	0.060
Holden	50	35	108	116	126	130	0.220	0.061
Holland	40	35	108	117	127	131	0.177	0.056
Holliston	40	35	110	120	129	133	0.225	0.060
Holyoke	35	35	106	114	123	128	0.166	0.055
Hopedale	40	35	110	120	129	134	0.210	0.059
Hopkinton	40	35	109	119	128	133	0.224	0.061
Hubbardston	503/990	35	106	115	124	129	0.226	0.063
Hudson	50	35	108	117	127	131	0.260	0.065
Hull	35	30	112	122	130	135	0.248	0.062
Huntington	50	40	105	114	122	127	0.162	0.055
Ipswich	50	30	108	118	126	131	0.335	0.073
Kingston	30	30	116	126	134	139	0.205	0.056
Lakeville	30	30	117	127	135	139	0.201	0.055
Lancaster	50	35	107	116	126	130	0.271	0.067
Lanesborough2	503/1433	40	104	111	119	125	0.168	0.057
Lawrence	50	30	107	116	125	129	0.368	0.077
Lee2	50	40	104	112	120	125	0.163	0.055
Leicester	503/903	35	108	117	126	131	0.199	0.059
Lenox2	503/1228	40	104	112	120	125	0.165	0.056
Leominster	60	35	107	115	125	129	0.284	0.068
Leverett	40	35	105	114	122	127	0.175	0.058
Lexington	40	30	109	118	127	132	0.296	0.069
Leyden2	603/867	40	104	112	120	125	0.179	0.059
Lincoln	40	35	109	118	127	131	0.286	0.068
Littleton	50	35	108	117	126	130	0.320	0.072
Longmeadow	35	35	107	116	125	129	0.170	0.055
Lowell	50	30	107	116	125	129	0.360	0.076
Ludlow	35	35	107	115	125	129	0.170	0.055
Lunenburg	603/452	35	107	115	124	129	0.318	0.072
Lynn	40	30	109	119	128	133	0.295	0.068
Lynnfield	50	30	109	118	127	131	0.320	0.071
Malden	40	30	109	119	128	132	0.288	0.068
Manchester	50	30	109	119	128	132	0.309	0.070
Mansfield	35	30	113	123	131	136	0.213	0.058
Marblehead	40	30	109	119	128	133	0.299	0.069
Marion	30	30	120	129	138	142	0.186	0.052
Marlborough	50	35	108	118	127	131	0.249	0.064
Marshfield	35	30	115	125	133	138	0.214	0.057
Mashpee	30	25	121	130	139	144	0.165	0.049
Mattapoisett	30	30	120	130	138	143	0.186	0.052
Maynard	50	35	108	118	127	131	0.282	0.068
Medfield	40	35	110	120	129	134	0.229	0.061
Medford	40	30	109	119	128	132	0.287	0.067
Medway	40	35	110	120	129	134	0.219	0.060
Melrose	40	30	109	119	128	132	0.297	0.069
Mendon	40	35	110	120	129	134	0.207	0.058
Merrimac	50	30	107	116	124	129	0.363	0.077
Methuen	50	30	107	116	125	129	0.372	0.078
Middleborough	30	30	117	126	134	139	0.203	0.055
Middlefield	603/1449	40	104	113	120	126	0.162	0.056
Middleton	50	30	108	118	127	131	0.334	0.073
Milford	40	35	110	120	129	133	0.214	0.059
Millbury	50	35	109	118	127	132	0.203	0.059
Millis	40	35	110	120	129	134	0.224	0.060
Millville	40	35	111	121	129	135	0.200	0.057
Milton	40	30	111	121	129	134	0.246	0.062
Monroe2	603/1932	40	104	111	119	125	0.171	0.059
Monson	40	35	108	116	126	130	0.173	0.055
Montague	50	35	105	113	121	127	0.177	0.058
Monterey	503/1491	40	104	113	120	126	0.162	0.055
Montgomery	40	40	105	114	122	127	0.163	0.055
Mount Washington2	40	40	104	113	120	125	0.165	0.054
Nahant	40	30	110	120	128	133	0.283	0.067
Nantucket	25	25	128	137	147	150	0.123	0.043
Natick	40	35	109	119	128	133	0.246	0.063
Needham	40	35	110	120	129	133	0.249	0.063
New Ashford2	503/1900	40	104	111	119	124	0.170	0.058
New Bedford	30	30	120	129	138	142	0.190	0.053
New Braintree	503/826	35	107	115	125	129	0.190	0.058
New Marlborough	50	40	105	113	121	126	0.163	0.054
New Salem	503/721	35	105	114	122	127	0.189	0.059
Newbury	50	30	108	116	125	130	0.348	0.075
Newburyport	50	30	107	116	125	130	0.350	0.076
Newton	40	30	109	119	128	133	0.264	0.065
Norfolk	40	35	111	121	130	135	0.219	0.059
North Adams2	603/1250	40	104	111	119	124	0.171	0.058
North Andover	50	30	108	116	125	130	0.365	0.077
North Attleborough	35	30	113	123	131	136	0.207	0.057
North Brookfield	503/804	35	107	116	125	130	0.190	0.058
North Reading	50	30	108	118	127	131	0.332	0.073
Northampton	40	35	105	114	123	128	0.167	0.056
Northborough	50	35	108	118	127	131	0.231	0.062
Northbridge	40	35	109	119	128	133	0.207	0.059
Northfield	60	35	104	112	120	126	0.193	0.061
Norton	35	30	114	124	132	137	0.210	0.057
Norwell	35	30	114	123	132	136	0.226	0.059
Norwood	40	35	111	121	129	135	0.232	0.061
Oak Bluffs	25	25	124	133	142	146	0.157	0.048
Oakham	503/907	35	107	116	125	129	0.203	0.060
Orange	60	35	105	113	122	127	0.199	0.061
Orleans	25	25	122	130	139	145	0.148	0.048
Otis	503/1506	40	105	113	121	126	0.162	0.055
Oxford	50	35	109	119	128	132	0.191	0.057
Palmer	40	35	107	116	125	130	0.173	0.056
Paxton	503/1054	35	108	116	126	130	0.206	0.060
Peabody	50	30	109	119	127	132	0.310	0.070
Pelham	40	35	105	114	123	128	0.177	0.057
Pembroke	30	30	115	124	133	138	0.215	0.058
Pepperell	60	35	107	115	124	128	0.369	0.077
Peru2	603/1846	40	104	112	120	125	0.164	0.056
Petersham	503/770	35	106	114	123	128	0.202	0.060
Phillipston	603/1088	35	106	114	123	128	0.220	0.063
Pittsfield2	503/1124	40	104	112	119	125	0.166	0.056
Plainfield2	603/1615	40	104	112	120	125	0.165	0.057
Plainville	40	35	112	123	131	136	0.208	0.057
Plymouth	30	30	117	127	135	140	0.196	0.055
Plympton	30	30	116	126	134	139	0.205	0.056
Princeton	503/959	35	107	116	125	129	0.233	0.063
Provincetown	25	25	118	127	135	140	0.181	0.053
Quincy	40	30	111	121	130	135	0.245	0.062
Randolph	35	30	112	122	130	135	0.233	0.061
Raynham	35	30	115	125	133	138	0.209	0.057
Reading	50	30	109	118	127	131	0.319	0.071
Rehoboth	35	30	115	125	134	138	0.202	0.056
Revere	40	30	110	119	128	133	0.282	0.067
Richmond2	50	40	104	112	120	125	0.168	0.056
Rochester	30	30	119	129	137	142	0.191	0.053
Rockland	35	30	113	123	131	136	0.224	0.059
Rockport	50	30	109	119	127	132	0.306	0.070
Rowe2	603/1516	40	104	111	119	125	0.170	0.058
Rowley	50	30	108	117	126	130	0.344	0.074
Royalston	603/944	35	105	113	122	127	0.230	0.064
Russell	40	40	105	114	122	127	0.163	0.055
Rutland	503/977	35	107	116	125	129	0.214	0.061
Salem	50	30	109	119	128	132	0.307	0.070
Salisbury	50	30	107	116	125	129	0.348	0.076
Sandisfield	503/1410	40	105	114	122	127	0.162	0.054
Sandwich	30	25	119	129	137	142	0.176	0.051
Saugus	40	30	109	119	128	132	0.298	0.069
Savoy2	603/1883	40	104	112	120	125	0.166	0.057
Scituate	35	30	113	123	131	136	0.229	0.060
Seekonk	35	30	115	125	134	138	0.201	0.056
Sharon	35	35	112	122	130	135	0.222	0.059
Sheffield2	40	40	104	113	120	125	0.164	0.054
Shelburne	50	40	104	112	120	125	0.171	0.058
Sherborn	40	35	109	120	128	133	0.236	0.062
Shirley	60	35	107	116	125	129	0.307	0.071
Shrewsbury	50	35	108	118	127	131	0.222	0.061
Shutesbury	40	35	105	114	122	127	0.180	0.058
Somerset	30	30	117	127	136	140	0.200	0.055
Somerville	40	30	109	119	128	133	0.277	0.066
South Hadley	35	35	106	114	123	128	0.167	0.056
Southampton	40	35	105	114	123	128	0.164	0.055
Southborough	40	35	109	119	128	132	0.237	0.062
Southbridge	40	35	109	118	127	132	0.182	0.056
Southwick	40	35	106	115	124	128	0.166	0.055
Spencer	50	35	108	117	126	130	0.193	0.058
Springfield	35	35	106	115	124	129	0.168	0.055
Sterling	50	35	107	116	125	129	0.255	0.065
Stockbridge2	50	40	104	112	120	125	0.164	0.055
Stoneham	40	30	109	119	127	132	0.306	0.070
Stoughton	35	35	112	122	131	136	0.225	0.059
Stow	50	35	108	117	126	130	0.280	0.067
Sturbridge	40	35	108	118	127	131	0.181	0.056
Sudbury	40	35	109	118	127	131	0.268	0.066
Sunderland	40	35	105	113	122	127	0.172	0.057
Sutton	50	35	109	119	128	133	0.199	0.058
Swampscott	40	30	109	119	128	133	0.295	0.068
Swansea	30	30	117	127	135	139	0.200	0.055
Taunton	35	30	115	125	134	138	0.206	0.056
Templeton	603/1003	35	106	114	123	128	0.233	0.064
Tewksbury	50	30	108	117	126	130	0.348	0.075
Tisbury	25	25	124	133	142	146	0.160	0.048
Tolland	50	40	105	114	123	127	0.163	0.054
Topsfield	50	30	108	118	126	131	0.339	0.074
Townsend	60	35	106	115	124	128	0.355	0.076
Truro	25	25	119	128	136	141	0.167	0.051
Tyngsborough	50	30	107	116	124	129	0.375	0.078
Tyringham2	50	40	104	113	120	125	0.162	0.055
Upton	40	35	109	119	128	133	0.211	0.059
Uxbridge	40	35	110	120	129	134	0.200	0.059
Wakefield	50	30	109	118	127	132	0.311	0.070
Wales	40	35	108	117	127	131	0.176	0.055
Walpole	40	35	111	121	130	135	0.225	0.060
Waltham	40	30	109	119	128	132	0.273	0.066
Ware	40	35	107	115	125	129	0.179	0.057
Wareham	30	30	119	129	137	142	0.188	0.053
Warren	40	35	107	116	125	130	0.180	0.057
Warwick	603/915	35	105	113	121	126	0.206	0.062
Washington2	603/1751	40	104	112	120	125	0.163	0.056
Watertown	40	30	109	119	128	133	0.272	0.066
Wayland	40	35	109	119	128	132	0.261	0.065
Webster	50	35	109	119	128	133	0.187	0.056
Wellesley	40	35	109	119	128	133	0.250	0.063
Wellfleet	25	25	120	129	137	143	0.160	0.050
Wendell	503/960	35	105	113	122	127	0.186	0.059
Wenham	50	30	109	118	127	131	0.327	0.072
W. Boylston	50	35	108	117	126	130	0.230	0.062
W. Bridgewater	35	30	114	124	132	137	0.213	0.057
W. Brookfield	40	35	107	116	125	130	0.183	0.057
W. Newbury	50	30	107	116	125	129	0.362	0.077
W. Springfield	35	35	106	115	124	129	0.167	0.055
W. Stockbridge2	40	40	104	112	120	125	0.166	0.056
W. Tisbury	25	25	124	133	142	146	0.160	0.048
Westborough	50	35	109	118	127	132	0.230	0.062
Westfield	40	35	106	114	123	128	0.165	0.055
Westford	50	35	107	116	125	129	0.338	0.074
Westhampton	50	40	105	114	122	127	0.164	0.056
Westminster	603/1007	35	106	115	124	128	0.262	0.067
Weston	40	35	109	119	128	132	0.269	0.066
Westport	30	30	119	128	137	141	0.195	0.053
Westwood	40	35	110	121	129	134	0.238	0.062
Weymouth	35	30	112	122	130	135	0.236	0.061
Whately	50	35	105	113	121	127	0.169	0.057
Whitman	35	30	114	124	132	137	0.219	0.058
Wilbraham	35	35	107	115	125	129	0.170	0.055
Williamsburg	50	40	105	113	121	127	0.165	0.056
Williamstown2	50	40	103	111	119	124	0.173	0.059
Wilmington	50	30	108	118	126	131	0.327	0.072
Winchendon	60	35	105	113	122	127	0.269	0.068
Winchester	40	30	109	119	127	132	0.296	0.069
Windsor2	603/1857	40	104	112	120	125	0.165	0.057
Winthrop	40	30	110	120	129	133	0.274	0.066
Woburn	50	30	109	118	127	132	0.305	0.070
Worcester	50	35	108	117	127	131	0.210	0.060
Worthington	603/1386	40	104	113	120	126	0.163	0.056
Wrentham	40	35	112	122	130	135	0.213	0.058
Yarmouth	30	25	123	131	139	145	0.152	0.048

NOTES:

1. The design flat roof snow load shall be the larger of the calculated flat roof snow load using Pg or the value of Pf listed in this table.

2. Special Wind Region. Local conditions may cause higher wind speeds than the tabulated values. See ASCE/SEI 7.

3. Increase Pg listed by 0.021 x (Site Elevation - Mean Elevation) when the Site Elevation exceeds the Mean Elevation.

4. Commentary: The basic wind speed, V, is equivalent to the formally defined ultimate wind speed, Vult, in 780 CMR. Vasd refers to allowable stress wind speeds.

1605.1 Add the following lines before Exceptions

For allowable stress design of structural steel in buildings and other structures, allowable stress design load combinations from ASCE 7, Section 2.4 that include the effects of wind or earthquake loads shall not be used. Instead two-thirds (2/3) of strength design load combinations from ASCE 7, Section 2.3 that include the effects of wind or earthquake loads shall be used.

1605.2 Delete subsection.

1607.12.2 Delete subsection.

1608.2 Revise section as follows:

1608.2Ground Snow Loads. The ground snow loads to be used in determining the design snow loads for roofs shall be determined in accordance with ASCE 7 or Figure 1608.2 for the contiguous United States and Table 1608.2 for Alaska. Site-specific case studies shall be made in areas designated "CS" in Figure 1608.2. Ground snow loads for sites at elevations above the limits indicated in Figure 1608.2 and for all sites within the CS areas shall be approved. Ground snow load determination for such sites shall be based on an extreme value statistical analysis of data available in the vicinity of the site using a value with a 2-percent annual probability of being exceeded (50-year mean recurrence interval). Snow loads are zero for Hawaii, except in mountainous regions as approved by the building official.

FIGURE 1608.5.1

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FIGURE 1608.5.2

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1608.4 through 1608.11 Add sections as follows:

1608.4Curved Roofs. Section 7.4.3 of ASCE 7 applies to curved roofs only. The effective loaded area of a curved roof shall be that area of the surface of the roof where the tangents to the surface have a slope of 50º or less. The total uniform snow load for curved roofs shall be Pf multiplied by the total horizontal projected area of the roof. This total load shall be applied uniformly over the effective loaded area of the roof.

1608.5Drifts on Multiple Level Roofs. For multiple stepped roofs similar to that shown in Figure 1608.5.1, the sum of all the roof lengths upwind above the drift under consideration, lu*, in Figure 1608.5.1, shall replace lu in Figure 7.7-2 of ASCE 7. For multiple level roofs similar to that shown in Figure 1608.5.2, if the total calculated height of a drift and the underlying uniform snow layer on the upwind side of a higher roof (hd + hb) is equal to or greater than 0.7(hb + hc), then the length, lu*, as shown in Figure 1608.5.2, shall be used in place of lu in Figure 7.7-2 of ASCE 7.

1608.6Very High Roof Separations. When the ratio hr/LT is greater than 1.0, where LT is the dimension in feet of the upper roof perpendicular to the wind flow (perpendicular to lu in Figure7.7-2 of ASCE 7) and hr = hb + hc, the drift surcharge load on the lower roof due to drifting of snow from the upper roof may be reduced. The reduced height of the drift surcharge, hdr, shall be not less than: hdr = hr (2 - hr/LT), except that when hr/LT is greater than 2.0, hdr shall be equal to zero.

1608.9Sliding Snow. In addition to the sliding snow load on a lower roof as required in section 7.9 of ASCE 7, the lower roof shall be designed for a windward drift surcharge at the wall separating the upper and lower roofs in accordance with Figure 1608.5.1 and Figure 7.7-2 of ASCE 7. The sliding snow load and the windward drift surcharge need not be considered to act concurrently.

1609.3 Replace the first paragraph with the following: 1609.3 Basic wind speed. The basic wind speed, V in mph, shall be determined in accordance with Table 1604.11. The basic wind speed, V, for the special wind regions indicated near mountainous terrain and near gorges shall be in accordance with the local jurisdiction requirements. The basic wind speeds, V, determined by the local authority having jurisdiction shall be in accordance with Chapter 26 of ASCE 7.

1610 Replace section as follows:

SECTION 1610 LATERAL SOIL AND HYDROSTATIC LOADS 1610.1 General. Basement, foundation, and retaining walls shall be designed to resist lateral loads due to soil and water pressure. Lateral soil pressure on said walls shall be determined in accordance with the principles of soil mechanics and as provided in 780 CMR 18.00. Floors or similar elements below the water table shall be designed to resist the upward pressure of the water.

EXCEPTION: Uninhabitable spaces with concrete floors on the ground with an under-slab drainage system, including sump pits and sump pumps, designed to keep the water level a minimum of one foot below the bottom of the floor slab need not be designed to resist water pressure.

1610.2Seismic Loads on Foundation Walls and Retaining Walls. Exterior foundation walls and retaining walls shall be designed to resist an allowable earthquake force, Fw, for horizontal backfill surface, equal to:

Fw = 0.1(SS)(Fa)([Gamma]t)(H)²

where SS is the maximum considered earthquake spectral response acceleration from Table 1604.11, Fa is the site coefficient from Table 1613.3.3(1), [Gamma]t is the total unit weight of the soil, and H is the height of the wall measured as the difference in elevation of finished ground surface or floor in front of and behind the wall. The resultant allowable earthquake force from the backfill shall be distributed as an inverted triangle over the height of the wall.

Surcharges that are applied over extended periods of time shall be included in the total static lateral soil pressure and their earthquake lateral force shall be computed and added to the force determined above. The point of application of the earthquake force from extended duration surcharge shall be determined on an individual case basis.

If the backfill or the existing soil behind the backfill consists of loose saturated granular soil, the potential for liquefaction of the backfill or existing soil adjacent to the wall during seismic loading shall be evaluated in accordance with the requirements of section 1806.4.

If the backfill or existing soil beyond the backfill is potentially subject to liquefaction, the increase in design lateral load on the foundation wall or retaining wall shall be determined by a registered design professional.

For wall strength design, a load factor of 1.43 shall be applied to the allowable earthquake force calculated above

1612.1 Revise section as follows:

1612.1General. Within flood hazard areas as established in section 1612.3, all new construction of buildings, structures and portions of buildings and structures, including substantial improvement and restoration of substantial damage to buildings and structures, and substantial repair of a foundation shall be designed and constructed to resist the effects of flood hazards and flood loads. For buildings that are located in more than one flood hazard area, the provisions associated with the most restrictive flood hazard area shall apply.

Replace subsection 1612.2 with the following:

1612.2Design and construction. The design and construction of buildings and structures located in flood hazard areas, including coastal high hazard areas and coastal A zones, shall be in accordance with Chapter 5 of ASCE 7 and ASCE 24. For minimum elevation requirements for lowest floor, bottom of lowest horizontal structural member, utilities, flood-resistant materials and wet and dry flood-proofing refer to tables in ASCE 24 which are to be amended as shown below. The design and construction of buildings and structures located in coastal dunes shall be in accordance with Appendix G.

Exceptions: Existing non-residential structures and non-residential portions of existing mixed use structures in Coastal A Zones shall be allowed to meet the A Zone requirements.

1612.3 Revise section as follows:

1612.3Establishment of Flood Hazard Areas.See 780 CMR 2.00 for definition of flood hazard areas.

1.3For dry floodproofed nonresidential buildings, construction documents shall include a statement that the dry floodproofing is designed in accordance with ASCE 24 and shall include the flood emergency plan specified in Chapter 6 of ASCE 24 and certified as-built level of protection.

1612.4 Revise section as follows:

1.3. For dry floodproofed nonresidential buildings, construction documents shall include a statement that the dry floodproofing is designed in accordance with ASCE 24 and shall include the flood emergency plan specified in Chapter 6 of ASCE 24 and certified as-built level of protection.

ASCE 24 Tables for flood-resistant materials and dry and wet-floodproofing - REVISED

		Flood Design Class 1	Flood Design Class 2	Flood Design Class 3	Flood Design Class 4
Elevation of Lowest Floor (A Zone)	All A Zones not Identified as Coastal A Zones	BFE +2 ft	BFE +2 ft	BFE +2 ft	BFE + 3 ft
Minimum Elevation of Lowest Horizontal Structural Member	All V Zones and Coastal A Zones	BFE + 3 ft	BFE + 3 ft	BFE + 3 ft	BFE + 3 ft
Minimum Elevation Below Which Flood-Damage-Resistant Materials Shall be Used	All A Zones not Identified as Coastal A Zones	BFE +2 ft	BFE +2 ft	BFE +2 ft	BFE + 3 ft
-	All V Zones and Coastal A Zones	BFE + 3 ft	BFE + 3 ft	BFE + 3 ft	BFE + 3 ft
Minimum Elevation** of Utilities and Equipment	All A Zones not Identified as Coastal A Zones	BFE +2 ft	BFE +2 ft	BFE +2 ft	BFE + 3 ft
	All V Zones and Coastal A Zones	BFE + 3 ft	BFE + 3 ft	BFE + 3 ft	BFE + 3 ft
Minimum Elevation of Dry Flood-proofing of non-residential structures and non-residential portions of mixed used buildings	All A Zones not Identified as Coastal A Zones	BFE +2 ft	BFE +2 ft	BFE +2 ft	BFE + 3 ft
	All V Zones and Coastal A Zones	Not Permitted	Not Permitted	Not Permitted	Not Permitted
Minimum Elevation of Wet Flood proofing***	All A Zones not Identified as Coastal A Zones	BFE +2 ft	BFE +2 ft	BFE +2 ft	BFE +3 ft
	Zone V	Not Permitted	Not Permitted	Not Permitted	Not Permitted
*Flood design class 1 structures shall be allowed below the minimum elevation if the structure meets the wet floodproofing requirements of ASCE 24-14 section 6.3.
**Unless otherwise permitted by ASCE 24-14 Chapter 7, except in V zones where protection of utilities and equipment below the indicated elevation is not accepted.
***Only if permitted by ASCE 24-14 section 6.3.1.

1613.1 Revise section as follows:

1613.1Scope. Every structure, and portion thereof, including nonstructural components that are permanently attached to structures and their supports and attachments, shall be designed and constructed to resist the effects of earthquake motions in accordance with ASCE 7, excluding Chapter 14 and Appendix 11A, but including Massachusetts Amendments to Tables 12.2-1 and 12.14-1. The seismic design category for a structure is permitted to be determined in accordance with section 1613 or ASCE 7, but seismic design category A shall not be used in the Commonwealth. Any structure that could satisfy the requirements of seismic design category A in section 1613 or ASCE 7 shall be assigned to seismic design category B for purposes of implementing 780 CMR.

Commentary on Provisions. Section 1613 presents criteria for the design and construction of buildings and nonbuilding structures subject to earthquake ground motion. The specified earthquake loads rely on post-elastic energy dissipation in the structure, and because of this fact, the provisions for design, detailing and construction shall be satisfied even for structures and members for which load combinations containing earthquake load produce lesser effects than other load combinations.

The purpose of section 1613 is to minimize the hazard to life of occupants of all buildings and nonbuilding structures, to increase the expected performance of high occupancy assembly and education buildings as compared to ordinary buildings, and to improve the capability of essential facilities to function during and after an earthquake. Because of the complexity of and the great number of variables involved in seismic design (e.g. variability in ground motion, soil types, dynamic characteristics of the structure, material strength properties, and construction practice), section 1613 presents only minimum criteria in general terms. These minimum criteria are considered to be prudent and economically justified for the protection of life safety in buildings subject to earthquakes and for improved capability of essential facilities to function immediately following an earthquake.

Absolute safety and prevention of damage, even in an earthquake event with a reasonable probability of occurrence, cannot be achieved economically in most buildings. The "design earthquake" ground motion specified in section 1613 may result in both structural and nonstructural damage. For most buildings designed and constructed according to the minimum requirements of section 1613, it is expected that structural damage from a major earthquake may be repairable, but the repair may not be economically feasible. For ground motions larger than the design earthquake, the intent of section 1613 is that there will be a low likelihood of building collapse.

1613.2.1 Revise subsection as follows: 1613.2.1

Mapped Acceleration Parameters. The parameters SS and S1 shall be determined from Table 1604.11.

NOTE: The following amendments pertain to ASCE 7. ASCE 7, TABLE 12.2-1.

Revise as follows:

Note p. Replace "ordinary moment frame" with "ordinary steel moment frame."

Limitations: Amend as follows:

Seismic Force-Resisting System	Seismic Design Category
A.3	B is NP
A.4	B is NP
A.9	B and C are NP
A.10	B is NP
A.11	B is NP
A.13	B and C are NP
A.14	B is NP
A.17	B and C are limited to 35 ft. and note 1.
B.6	B is NP
B.7	B is NP
B.18	B and C are NP
B.19	B is NP
B.20	B is NP
B.24	B and C are limited to 35 ft. and note 1.
C.7	B is NP
E.3	B and C are NP
F	B is NP
H	B and C are limited to 100 ft. and 65 ft., respectively and note 2

NOTE 1: Permitted only at exterior walls and firerated walls and not permitted for buildings in Risk Category IV and not permitted for buildings where the seismic weight of any laterally supported level (floor or roof) exceeds 25 psf.

NOTE 2: Connections, including connections to foundations, shall be designed for two times the computed forces and moments resulting from seismic loads, in combination with other loads, as applicable, but need not be designed for forces greater than the expected nominal yield strength (RyFyAg) of diagonal braces in braced frames or 1.1 times the expected flexural capacity of beams (1.1RyMp) in moment frames. Columns that are part of the seismic forceresisting system shall satisfy the requirements of section D1.4a of ANSI/AISC 341 Seismic Provisions for Structural Steel Buildings. K-Braced Frames shall not be permitted. Beams in V-Type and Inverted VType Braced Frames shall meet the following additional requirements:

a. A beam that is intersected by braces shall be continuous between columns.

b. A beam that is intersected by braces shall be designed to support the effects of all tributary dead and live loads from load combinations stipulated by 780 CMR16.00 assuming that braces are not present.

c. Top and bottom flanges of the beam at the point of intersection of braces shall be designed to support a horizontal force perpendicular to the longitudinal axis of the beam that is equal to two percent of the nominal beam flange strength: F[Gamma]b_ftbf.

ASCE 7, TABLE 12.14-1 Revise as follows: Limitations: Amend as follows:

Seismic Force-Resisting System	Seismic Design Category
A.3	B is NP
A.4	B is NP
A.9	B is NP
A.10	B is NP
A.11	B is NP
A.15	See note 1.
B.6	B is NP
B.7	B is NP
B.18	B is NP
B.19	B is NP
B.20	B is NP
B.24	See note 1.

NOTE 1: Permitted only at exterior walls and fire-rated walls and not permitted for buildings in Risk Category IV and not permitted for buildings where the seismic weight of any laterally supported level (floor or roof) exceeds 25 psf.

780 CMR, CHAPTER 16

Amended by Mass Register Issue 1532, eff. 10/11/2024.