I too wish this was feature in BS3. You'll have to create your own solution.
My typical workaround is just as Foundation does it, by using percentages to define width, the nth-child selector, and adjusting margins.
[class*="block-grid-"] {
display: block;
padding: 0;
margin: 0 -0.55556rem;
}
[class*="block-grid-"] > li {
display: block;
height: auto;
float: left;
padding: 0 0.55556rem 1.11111rem;
}
.small-block-grid-3 > li {
width: 33.33333%;
list-style: none;
}
.small-block-grid-3 > li:nth-of-type(1n) {
clear: none;
}
.small-block-grid-3 > li:nth-of-type(3n+1) {
clear: both;
}