Reinforced concrete structure joint including smart memory alloy bars and method of manufacturing the same
A reinforced concrete structure includes a first elongated concrete body extending in a first direction and a second elongated concrete body extending in a second direction, different from the first direction, and connected to the first elongated body. The first concrete body may include a first metallic reinforcement member embedded along its length. The second concrete body may include: a) plurality of second metallic reinforcement members, formed of a smart memory alloy, embedded along its length, and b) at least one third metallic reinforcement member, which may be formed of material other than a smart memory alloy, extending along its length. In a lateral cross-sectional area of the second concrete body, a cross-sectional area of the second and third metallic reinforcement members combined divided by the cross-sectional area of the third metallic reinforcement member ranges from about 3 to about 3.3.
1 . A structure comprising:
a first structural member extending in a first direction; and
a second structural member extending in a second direction, said second direction crossing the first direction, the first and second structural members being connected to one another;
wherein the first structural member includes a first concrete body with at least one first metallic reinforcement member embedded in the first concrete body,
wherein the second structural member includes:
a second concrete body;
a plurality of second metallic reinforcement members embedded in the second concrete body, the plurality of second metallic reinforcement members extending in a length direction of the second concrete body, wherein each one of the plurality of second metallic reinforcement members includes a smart memory alloy along at least a portion of a length thereof; and
at least one third metallic reinforcement member embedded in the second concrete body, the at least one third metallic reinforcement member extending in the length direction of the second concrete body,
wherein, in a lateral cross-section of the second structural member, taken along a portion of the second structural member that extends adjacent to the first structural member or at a distance from the first structural member, ratio R applies,
wherein
R
=
A
B
,
wherein A equals a sum of a cross-sectional area of the plurality of second metallic reinforcement members and a cross-sectional area of the at least one third metallic reinforcement member, and
B equals the cross-sectional area of the at least one third metallic reinforcement member, and
wherein R ranges from about 3 to about 3.3,
wherein the plurality of second metallic reinforcement members and the at least one third metallic reinforcement member are arranged in a first group of reinforcement members and in a second group of reinforcement members,
wherein the second group of reinforcement members includes:
a third one and a fourth one of the plurality of second metallic reinforcement members; and
a second one of the at least one third metallic reinforcement member,
wherein, in the lateral cross-section of the second structural member, ratio R2 applies,
wherein
R
2
=
A
2
B
2
,
wherein A2 equals a sum of a cross-sectional area of the third one of the plurality of second metallic reinforcement members, the fourth one of the plurality of second metallic reinforcement members and the second one of the at least one third metallic reinforcement member, and
B2 equals a cross-sectional area of the second one of the at least one third metallic reinforcement member, and
wherein R2 ranges from about 3 to about 3.3,
wherein a lightweight concrete mix used for forming at least one selected from the group consisting of the first and second concrete bodies includes:
410 kg/m 3 cement;
420 kg/m 3 lightweight coarse aggregate;
420 kg/m 3 lightweight fine aggregate;
240 kg/m 3 silica sand;
260 kg/m 3 water; and
8 kg/m 3 Superplasticizer.
2 . The structure of claim 1 , wherein R equals about 3.17.
3 . The structure of claim 1 , wherein the plurality of second metallic reinforcement members and the at least one third metallic reinforcement member are arranged in a row and spaced apart from one another.
4 . The structure of claim 3 , wherein the row includes:
a first one and a second one of the plurality of second metallic reinforcement members; and
a first one of the at least one third metallic reinforcement member.
5 . The structure of claim 4 , wherein the first one of the at least one third metallic reinforcement member is arranged between the first one and the second one of the plurality of second metallic reinforcement members.
6 . The structure of claim 1 , wherein the first group of reinforcement members includes:
a first one and a second one of the plurality of second metallic reinforcement members; and
a first one of the at least one third metallic reinforcement member,
wherein, in the lateral cross-section of the second structural member, ratio R1 applies,
wherein
R
1
=
A
1
B
1
,
wherein A1 equals a sum of a cross-sectional area of the first one of the plurality of second metallic reinforcement members, the second one of the plurality of second metallic reinforcement members and the first one of the at least one third metallic reinforcement member, and
B1 equals a cross-sectional area of the first one of the at least one third metallic reinforcement member, and
wherein R1 ranges from about 3 to about 3.3.
7 . The structure of claim 6 , wherein R1 equals about 3.17.
8 . The structure of claim 6 , wherein, in the first group of reinforcement members, the first one of the plurality of second metallic reinforcement members, the second one of the plurality of second metallic reinforcement members and the first one of the at least one third metallic reinforcement member are spaced apart from one another, and
wherein the first one of the at least one third metallic reinforcement member is disposed between the first one and the second one of the plurality of second metallic reinforcement members.
9 . The structure of claim 8 , wherein the first one of the plurality of second metallic reinforcement members, the second one of the plurality of second metallic reinforcement members and the first one of the at least one third metallic reinforcement member are arranged in a row.
10 . The structure of claim 6 , wherein, in the second group of reinforcement members, the third one of the plurality of second metallic reinforcement members, the fourth one of the plurality of second metallic reinforcement members and the second one of the at least one third metallic reinforcement member are spaced apart from one another, and
the wherein the second one of the at least one third metallic reinforcement member is disposed between the third one of the plurality of second metallic reinforcement members and the fourth one of the plurality of second metallic reinforcement members.
11 . The structure of claim 10 , wherein the third one of the plurality of second metallic reinforcement members, the fourth one of the plurality of second metallic reinforcement members and the second one of the at least one third metallic reinforcement member are arranged in a row.
12 . The structure of claim 1 , wherein the smart memory alloy of the plurality of second metallic reinforcement members includes nickel and titanium.
13 . The structure of claim 12 , wherein the smart memory alloy includes about 55.68% by weight nickel and about 44.21% by weight titanium.
14 . The structure of claim 1 , wherein at least one selected from the group consisting of the plurality of second metallic reinforcement members and the at least one third metallic reinforcement member further extends into the first concrete body of the first structural member by about half of a width of the first concrete body, thereby being embedded in said first concrete body.
15 . A method of forming a reinforced concrete structure, comprising:
forming a first formwork for a first structural member;
forming a second formwork for a second structural member, the second formwork intersecting the first formwork and extending in a different direction than the first formwork;
disposing at least one first metallic reinforcement member in the first formwork;
disposing plurality of second metallic reinforcement members in the second formwork, the plurality of second metallic reinforcement members extending in a length direction of the second formwork, wherein the plurality of second metallic reinforcement members includes a smart memory alloy along at least a portion of a length thereof;
disposing at least one third metallic reinforcement member in the second formwork, the at least one third metallic reinforcement member extending in the length direction of the second formwork;
pouring concrete in the first formwork; and
pouring concrete in the second formwork,
wherein, in a lateral cross-section of the second formwork, taken along a portion of the second formwork that extends adjacent to the first formwork or at a distance from the first formwork, ratio R applies,
wherein
R
=
A
B
,
wherein A equals a sum of a cross-sectional area of the plurality of second metallic reinforcement members and a cross-sectional area of the at least one third metallic reinforcement member, and
B equals the cross-sectional area of the at least one third metallic reinforcement member, and
wherein R ranges from about 3 to about 3.3,
wherein the plurality of second metallic reinforcement members and the at least one third metallic reinforcement member are arranged in a first group of reinforcement members and in a second group of reinforcement members,
wherein the second group of reinforcement members includes:
a third one and a fourth one of the plurality of second metallic reinforcement members; and
a second one of the at least one third metallic reinforcement member,
wherein, in the lateral cross-section of the second formwork, ratio R2 applies,
wherein
R
2
=
A
2
B
2
,
wherein A2 equals a sum of a cross-sectional area of the third one of the plurality of second metallic reinforcement members, the fourth one of the plurality of second metallic reinforcement members and the second one of the at least one third metallic reinforcement member, and
B2 equals a cross-sectional area of the second one of the at least one third metallic reinforcement member, and
wherein R2 ranges from about 3 to about 3.3,
wherein the concrete poured in at least one formwork selected from the group consisting of the first formwork and the second formwork for forming at least one selected from the group consisting of a first concrete body of the first structural member and a second concrete body of the second structural member, is a lightweight concrete mix, said lightweight concrete mix including:
410 kg/m 3 cement;
420 kg/m 3 lightweight coarse aggregate;
420 kg/m 3 lightweight fine aggregate;
240 kg/m 3 silica sand;
260 kg/m 3 water; and
8 kg/m 3 Superplasticizer.
16 . The method of claim 15 , further comprising:
waiting a period of time for the concrete poured in the first and second formworks to cure; and
removing the first and second formworks.
17 . The method of claim 15 , wherein the smart memory alloy includes nickel and titanium.