TS 500 / TSC 2018 Structural Design Guide

1.1 Concrete — TS 500:2000 Table 2.1

Design compressive strength: f_cd = 0.85·f_ck/γ_c  (γ_c = 1.5) → f_cd = 0.567·f_ck

Modulus of elasticity: E_c = 3250·√f_ck + 14000 (MPa)

Class	fck (MPa)	fcd (MPa)	fctk (MPa)	fctd (MPa)	Ec (MPa)
C16	16	9.1	1.40	0.93	27,000
C20	20	11.3	1.60	1.07	28,500
C25	25	14.2	1.80	1.20	30,250
C30	30	17.0	1.90	1.27	31,820
C35	35	19.8	2.10	1.40	33,230
C40	40	22.7	2.20	1.47	34,520
C45	45	25.5	2.40	1.60	35,760
C50	50	28.3	2.50	1.67	36,970

f_ctd = f_ctk/1.5. TSC 2018 §7.2.2: minimum C25 for HD-MRF / HD-SW; C20 minimum for LD-MRF / LD-SW.

See Concrete Properties Reference for full class properties.

1.2 Reinforcing Steel — TS 500:2000

Design yield strength: f_yd = f_yk/γ_s  (γ_s = 1.15). E_s = 200,000 MPa.

Grade	fyk (MPa)	fyd (MPa)	Type	Seismic use
S220	220	191	Plain bars (Class I)	Not permitted for primary seismic elements
S420	420	365	Deformed (Class II)	LD systems acceptable
B420C	420	365	Deformed — seismic grade C	HD-MRF / HD-SW required
B500C	500	435	Deformed — seismic grade C	HD-MRF / HD-SW required

TSC 2018 §7.2.3: B420C or B500C mandatory for primary seismic elements in high-ductility systems.

→ Rebar Properties & Bar Size Reference

1.3 Partial Safety Factors

Material	γ (ULS)
Concrete (γc)	1.50
Reinforcing steel (γs)	1.15

2.1 Seismic Design Class (DTS) — TSC 2018 Table 3.4

DTS is determined from design spectral acceleration S_DS and BUC:

SDS	BUC 1 & 2	BUC 3 & 4
SDS ≥ 0.75	DTS 1	DTS 1a
0.33 ≤ SDS < 0.75	DTS 2	DTS 2a
SDS < 0.33	DTS 3	DTS 4

BUC 1 = critical (hospitals, emergency) · BUC 2 = important (schools, high-occupancy) · BUC 3 = normal (residential, office) · BUC 4 = low risk (storage, agriculture)

2.2 Required Ductility Level by DTS

DTS	Minimum Required System
DTS 1, 1a	High Ductility only — HD-MRF or HD-SW or Dual HD
DTS 2, 2a	High Ductility preferred; LD systems permitted with height restriction
DTS 3	HD or LD systems permitted
DTS 4	No special seismic ductility detailing required

2.3 Response Modification Factors — TSC 2018 Table 4.1

R = system behavior factor (response modification); D = overstrength factor. The reduced design spectral acceleration is S_ad(T) = S_aR(T) / R_a(T), where R_a = R/I for T ≥ T_B.

Reinforced Concrete Systems

System	R	D	Permitted DTS	Key Requirements (TSC 2018)
Moment Resisting Frame Systems
High-Ductility RC MRF YDMÇ	8	3	All (1, 1a, 2, 2a, 3, 4)	§7.3/§7.4 ductile detailing · C25 min · B420C/B500C · Strong-column–weak-beam: ΣMra,col ≥ 1.2·ΣMra,beam · Column axial ratio Nd/(Ac·fcd) ≤ 0.40 in DTS 1,1a
Limited-Ductility RC MRF SDMÇ	4	2.5	2a, 3, 4 only	§7.8/§7.9 limited ductility detailing · C20 min · S420 acceptable · Not permitted in DTS 1 or 1a
Shear Wall Systems
High-Ductility RC Shear Wall — Coupled Bağlantı kirişli YDPB	7	2.5	All (1, 1a, 2, 2a, 3, 4)	hw/lw ≥ 2.0 · Coupling beams with diagonal reinforcement · Boundary elements per §7.6.6 · C25 min · B420C/B500C
High-Ductility RC Shear Wall — Uncoupled YDPB	6	2.5	All (1, 1a, 2, 2a, 3, 4)	hw/lw ≥ 2.0 · Boundary elements required per §7.6.6 · C25 min · B420C/B500C · Web ρh, ρv ≥ 0.0025
Limited-Ductility RC Shear Wall SDPB	4	2	2a, 3, 4 only	§7.10 detailing · hw/lw ≥ 2.0 · Not permitted in DTS 1 or 1a · C20 min
Dual Systems (Frame + Shear Wall)
RC Dual — HD MRF + HD Shear Wall YDMÇ + YDPB	7	2.5	All (1, 1a, 2, 2a, 3, 4)	Frame must independently resist ≥ 25% of storey shear · Both systems designed and detailed for full ductility · C25 min · B420C/B500C
RC Dual — LD MRF + LD Shear Wall SDMÇ + SDPB	4	2	3, 4 only	Not permitted in DTS 1, 1a or 2, 2a · §7.8–§7.10 limited ductility detailing for both systems

Steel Systems

System	R	D	Permitted DTS	Key Requirements (TSC 2018)
Moment Resisting Frame Systems
High-Ductility Steel MRF YDÇMÇ	8	3	All (1, 1a, 2, 2a, 3, 4)	§9.2 fully restrained moment connections · Seismic compactness (λps) · Panel zone shear check · Strong-column–weak-beam required · Reduced beam section (RBS) or equivalent
Limited-Ductility Steel MRF SDÇMÇ	4	2.5	2a, 3, 4 only	§9.9 ordinary moment connection detailing · Not permitted in DTS 1 or 1a
Concentrically Braced Frame Systems
High-Ductility Concentrically Braced Frame YDÇKK	6	2	All (1, 1a, 2, 2a, 3, 4)	§9.4 special CBF detailing · Brace slenderness KL/r ≤ 200 · Gusset plates with balanced brace pairs (V- or inverted-V braces require beam to resist unbalanced force) · Seismic compactness of beams/columns
Limited-Ductility Concentrically Braced Frame SDÇKK	4	2	2a, 3, 4 only	§9.10 ordinary CBF detailing · Not permitted in DTS 1 or 1a
Eccentrically Braced & Special Systems
High-Ductility Eccentrically Braced Frame YDÇDKK / EBF	7	2	All (1, 1a, 2, 2a, 3, 4)	§9.5 EBF link beam design governs · Link rotation angle limits: e ≤ 1.6Mp/Vp (shear link) or e ≥ 2.6Mp/Vp (moment link) · Link rotation: γp ≤ 0.08 rad (shear), 0.02 rad (moment) · Full lateral bracing of link beam
Buckling-Restrained Braced Frame BRBÇ / BRBF	7	2.5	All (1, 1a, 2, 2a, 3, 4)	§9.7 BRBF requirements · Qualification testing of BRB elements required · Adjusted brace strength Ry·Fy·Asc used for connection and frame design · Seismic compactness of beams and columns
Dual Systems (Frame + Braced Frame)
Steel Dual — HD MRF + HD Braced Frame YDÇMÇ + YDÇKK	7	2.5	All (1, 1a, 2, 2a, 3, 4)	Frame must independently resist ≥ 25% of storey shear · Both systems designed and detailed to full ductility requirements
Steel Dual — LD MRF + LD Braced Frame SDÇMÇ + SDÇKK	4	2.5	3, 4 only	Not permitted in DTS 1, 1a or 2, 2a · Limited ductility detailing for both systems

Values from TSC 2018 Table 4.1. D = overstrength factor (dayanım fazlalığı katsayısı). Building height limits apply in certain DTS categories — verify in TSC 2018 Table 4.1 footnotes for definitive design.

2.4 Site Classes — TSC 2018 Table 2.1

Site Class	Description	VS30 (m/s)
ZA	Hard rock	> 1500
ZB	Rock	760–1500
ZC	Very dense soil / soft rock	360–760
ZD	Stiff soil	180–360
ZE	Soft soil	≤ 180

S_DS = F_SS·S_S, S_D1 = F₁·S₁ — site class amplification factors F_SS and F₁ from TSC Tables 2.2 and 2.3. S_S and S₁ from AFAD seismic hazard maps (TDTH).

3.1 Minimum Beam Depths — TS 500:2000 Cl. 6.1.5

Recommended minimum h/L ratios for deflection control:

Support Condition	Beam	One-way Slab
Simply supported	L/10	L/30
One end continuous	L/12	L/35
Both ends continuous	L/15	L/40
Cantilever	L/5	L/12

These are minimum h values. Where deflection is critical, explicit calculation per TS 500 Cl. 6.5 is required.

→ Beam Flexural & Shear Design Calculator · Slab Design Calculator

3.2 Non-Seismic Minimum Dimensions

Element	Minimum	Reference
Beam width bw	Practical min 200 mm	—
Column min dimension	Practical min 200 mm; bk/hk ≥ 0.25	TS 500 Cl. 6.1.5
Slab thickness	min 80 mm (one-way)	TS 500 Cl. 6.1.5

3.3 Seismic Minimum Dimensions — TSC 2018

Element	HD-MRF Requirement	Reference
Beam width bw	≥ 250 mm; bw/h ≥ 0.3	§7.3.1
Column min dimension	≥ 300 mm; bk/hk ≥ 0.4	§7.4.1
Column axial force ratio	Nd/(Ac·fcd) ≤ 0.40 (DTS 1,1a)	§7.4.1
Shear wall aspect ratio	hw/lw ≥ 2.0 for ductile wall	§7.6.1

4.1 Dead Loads — TS 498 Table 2

Unit weights: RC 25 kN/m³, plain concrete 23 kN/m³, brick masonry 18–20 kN/m³, cement screed 21 kN/m³. Floor finish + screed: typically 1.0–1.5 kN/m².

4.2 Imposed Loads — TS 498 Table 3 (selected)

Occupancy	qk (kN/m²)
Residential	2.0
Office	3.0
Classroom / meeting room	3.0–4.0
Retail / shopping	4.0–5.0
Storage / archive	5.0–10.0
Parking (light vehicles)	2.5–4.0

4.3 Wind & Snow

Wind: TS 498 and TS EN 1991-1-4 applied in practice. Basic wind speed from Turkish national maps (V_b,0). Procedure follows EN 1991-1-4 with Turkish National Annex values.

Snow: TS 498 Table 7 / TS EN 1991-1-3. Ground snow load s_k from national snow map; roof load s = μ_i·C_e·C_t·s_k.

5.1 Earthquake Levels — TSC 2018 §2.2

Level	Return Period	Probability (50 yr)	Design purpose
DD-1	2475 years	2%	Collapse prevention (performance check)
DD-2	475 years	10%	Standard design earthquake
DD-3	72 years	50%	Service level (limited damage check)
DD-4	43 years	68%	Long-period design

Standard new building design uses DD-2 (475-year) for strength; DD-3 for interstorey drift checks.

5.2 Horizontal Design Spectrum — TSC 2018 §2.3 (DD-2)

Short-period region (0 ≤ T ≤ T_A): S_aR(T) = (0.4 + 0.6·T/T_A)·S_DS

Plateau (T_A ≤ T ≤ T_B): S_aR(T) = S_DS

Descending (T_B ≤ T ≤ T_L): S_aR(T) = S_D1/T

Long-period (T > T_L): S_aR(T) = S_D1·T_L/T²

Corner periods: T_A = 0.2·T_B, T_B = S_D1/S_DS, T_L = 6 s

5.3 Reduced Design Spectrum — TSC 2018 §4.3.3

S_ad(T) = S_aR(T) / R_a(T)

For T ≥ T_B: R_a(T) = R/I (I = BUC importance factor, see Section 2.1)

For T < T_B: R_a(T) = D + (R/I − D)·T/T_B (linear transition)

Minimum base shear: V_t,min = 0.04·m_t·S_DS·g — §4.3.3.3

5.4 Base Shear & Vertical Distribution (ELF)

V_t = m_t·S_ad(T₁) — §4.3.3.2

T₁ ≈ C_t·H^3/4: C_t = 0.07 (RC frames), 0.05 (walls/other)

Storey forces: F_i = V_t·(m_i·H_i^α) / Σ(m_j·H_j^α) — §4.3.4

α = 1.0 (T₁ ≤ 0.5 s), α = 2.0 (T₁ ≥ 2.0 s), linear interpolation between.

Additional top storey force: ΔF_N = 0.07·T₁·V_t (if T₁ > 0.7 s) — §4.3.4

6.1 ULS Strength Combinations — TSC 2018 §4.4.3

Combination	Equation
G1	1.4G
G2	1.2G + 1.6Q + 0.5(Qa or S)
G3	1.2G + 1.6(Qa or S) + max(0.5Q, 0.8W)
G4	1.2G + 1.6W + 0.5Q + 0.5(Qa or S)
G5	1.2G + 1.0Ed + 1.0Q + 0.3S
G6	0.9G + 1.6W
G7	0.9G + 1.0Ed

G = dead load, Q = live load, Q_a = roof live load, S = snow, W = wind, E_d = seismic design force.

6.2 Seismic Mass

m_t = Σ(G_i + n·Q_i)/g — §4.4.2

n = 0.3 for residential/office occupancies; n = 0.6 for storage; n = 0 for roof live/snow.

7.1 Flexural Design — TS 500:2000 Cl. 7.1

Rectangular stress block (similar to EC2): depth factor = 0.85 for f_ck ≤ 30 MPa.

Normalised moment: μ = M_d/(f_cd·b·d²)

Mechanical reinforcement ratio: ω = 1 − √(1 − 2μ)

Required steel: A_s = ω·f_cd·b·d / f_yd

Minimum steel — TS 500 Cl. 9.3.1: A_s,min = 0.8·f_ctd·b_w·d / f_yd

Maximum steel — Cl. 9.3.1: ρ_max = 0.85·β₁·(f_cd/f_yd)·(ε_cu/(ε_cu+ε_yd))

→ Beam Flexural Design Calculator

7.2 Shear Design — TS 500:2000 Cl. 8

Concrete contribution (no shear reinforcement):

V_cr = 0.65·f_ctd·b_w·d  (simplified, Cl. 8.1.2)

With stirrups: V_r = V_cr + (A_sw/s)·f_ywd·d·cot α

Maximum shear: V_r,max = 0.22·f_cd·b_w·d  (Cl. 8.2.4)

→ Beam Shear Design Calculator

7.3 Column Design — TS 500:2000 Cl. 7.4

Short column (λ = L₀/i ≤ 40): P-M interaction. See Column PMM Design Calculator.

Slender column (λ > 40): second-order moments must be added per TS 500 Cl. 7.4.

Min. steel: A_s ≥ 0.01·A_c; max: A_s ≤ 0.04·A_c (0.06 at laps).

7.4 Torsion — TS 500:2000 Cl. 8.3

Threshold: T_cr = 0.65·f_ctd·A_cp²/p_cp. Below this threshold, torsion may be neglected in combination with shear. Above threshold: closed stirrups + longitudinal reinforcement per Cl. 8.3.

→ Beam Torsion Design Calculator

8.1 Non-Seismic Detailing (DTS 4)

Standard cover, development lengths, and stirrup spacing per TS 500:2000 Cl. 9–11. No special ductile detailing required.

→ Development Length Calculator (TS 500)

8.2 High-Ductility (HD-MRF) Beam Detailing — TSC 2018 §7.3

Confinement region: 2h from face of column at each end — §7.3.4

Hoop spacing in confinement: s_e ≤ min(h/4, 8d_bL, 24d_bw, 200 mm) — §7.3.4.1

Outside confinement: s ≤ h/2; minimum d_bw ≥ 8 mm

Minimum 2 bars top and bottom throughout span. Positive moment capacity at support face ≥ 50% of negative moment capacity — §7.3.2.

8.3 High-Ductility (HD-MRF) Column Detailing — TSC 2018 §7.4

Confinement zone: l₀ = max(H_k/6, b_k, h_k, 500 mm) from each column end — §7.4.3.1

Hoop spacing in confinement: s_e ≤ min(b₀/3, 6d_bL, 150 mm) — §7.4.4.1

b₀ = confined core dimension (to centreline of outermost hoop)

Strong column–weak beam: ΣM_ra(col) ≥ 1.2·ΣM_ra(beam) at each joint — §7.4.2

8.4 Limited-Ductility (LD-MRF) Detailing — TSC 2018 §7.8 / 7.9

Beam confinement region: 2h from face of column.

Hoop spacing in confinement: s_e ≤ min(h/3, 10d_bL, 200 mm) — §7.8.3

Column confinement: l₀ same as HD-MRF; hoop spacing: s_e ≤ min(b₀/2, 8d_bL, 200 mm) — §7.9.3

8.5 Shear Wall Boundary Elements — TSC 2018 §7.6

Boundary elements required when compression zone exceeds threshold. High ductility: detailed transverse reinforcement over l_c ≥ max(0.15·l_w, 1.5·b_w).

9.1 Interstorey Drift Limits — TSC 2018 §4.9

Reduced interstorey drift: δ_i = R·u_i/I (amplified from elastic analysis)

Condition	Limit δi,max/hi
RC frames with brittle infill	0.008
RC frames with ductile / no infill	0.016
Seismic isolation systems	Per isolation design

Checked under DD-3 (72-year) earthquake — §4.9.1.

9.2 Diaphragm Design — TSC 2018 §4.5.6

Floor slabs assumed rigid diaphragms in standard buildings. Collector elements and chord reinforcement designed for in-plane diaphragm forces. Flexible diaphragm modelling required for irregular plans or large openings.

9.3 Irregularity Checks — TSC 2018 §3.6

TSC defines plan irregularities (A1–A3) and vertical irregularities (B1–B3). Buildings with certain irregularities must use MRSA rather than ELF — §4.3.2.

• A1: Torsion irregularity — ratio of max/mean drift > 1.2 at any storey
• B1: Soft storey — storey stiffness < 70% of storey above (or < 80% of avg 3 above)
• B2: Mass irregularity — storey mass > 1.5× adjacent storey mass