A sole-source contract modification is planned for Tutor Perini Corporation-Nan Inc. A Joint Venture for critical emergency waterfront stabilization repairs to the Glass Breakwater at Apra Harbor, Guam, addressing damage from Typhoon Sinlaku and preventing further deterioration. The modification is valued at $19,624,552.00 and covers procurement and placement of additional armor stone. The action is justified under statutory authority for unusual and compelling urgency, as providing a fair opportunity would cause unacceptable delays.